Apple Watch Ultra 4 | Hacker News Reader

Apple Watch Ultra 4

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101 pointstech234a160 comments

The Ultra 2 was sold to me as the watch that can do Siri without network connectivity. That was very useful to me to leave reminders for stuff I think about while on a run without the phone.

3 years later, Apple releases the OS 27 versions and Siri got improved to the point where it can’t work on-device any more on said Ultra 2

So to get the feature back which I paid for and which was specifically used to sell me the device and which now has been taken away from me, I just have to… buy the next hardware generation?

And how long will that last before they decide to remove the feature again?

Thankfully, the Ultra 4 provides some other compelling features making this less painful, but I would have expected at least a toggle to keep old Siri on the old watch. New Siri over the network is impossibly slow and buggy (I made the mistake of installing the betas, so there’s no way back now)

I seriously am surprised there are no class action suits around the crippling of older devices that is happening these days. Google Home speakers are prime example of that.

Yeah I took a 2012 iMac , loaded Ubuntu and it runs latest Firefox and chrome like lightening. Take same 2012 iMac and run latest macOS it is allowed to run and it runs super super slow.

This is clearly by design. They like to advertise long support windows but they cripple older devices through software and OS features causing older devices to run much much slower.

I have seen this for years from Apple and it would be hard to convince me that this isn’t done by design.

Sure, but what I am talking about here is even worse: they're taking away features that originally sold the device, so imagine they removed keyboard backlight after 5 years because they no longer want to maintain the cloud backend (hypothetically).

Apple's marketing department is amazing, however, they just don't line up with the engineering department. I quit Apple long ago because they overhyped so many things, it feels misleading intentionally sometimes.

Very good marketers though, I'll give them that.

On some of my devices, I have stopped updating the OS.

That works for a while until you have to do a restore from backup and the apps that used to be on the phone will not reinstall because they dropped support.

Also make sure to have optimize storage off, so apps don’t just disappear randomly.

Absolutely par for the course for Apple. They wrecked both my iPhone 4S and iPad 2 with the version 7 of the OS to the almost unusable state. I remember reading about several such "upgrades" in more recent years too.

I don't think Apple will hear your complaint if you keep giving them money.

> I would have expected at least a toggle to keep old Siri on the old watch.

Nasty destructive surprises in upgrades.

Years ago I had lots of archival material organized on my Mac under the root "/". Why not, right? It's a Unix-y system and Linux lets you put stuff anywhere. I had directory trees copied from old hard drives. Personal history.

So along comes a macOS upgrade and BLAM! all my stuff there gets deleted without warning or so much as a Hi how do you do.

You can still turn it off. In Content Restrictions there is a drop down to limit to the old Siri. There is also a prompt, if you try to turn off Siri completely, to revert to the old Siri. Then that setting applies to the Watch too.

The first thing they mention is the "great" battery life and it is still only just over 2 days, great.

I desperately wish apple would release a viable competitor to the garmin fenix line but they can't with that battery life. Garmin UX and software overall is such dogshit, and to have Apple UX with garmin raw performance (battery life, GPS tracking accuracy, activity modes) would be perfect. Apple could never though because the fenix was designed from the ground up as an embedded device microcontroller, whereas apple watch is a general purpose computer with a GPU.

I suspect the screen is also a big battery drain. I dont find color useful in a watch so perhaps a greyscale version with no GPU. Apple could definitely do 7+ day batter life if they wanted.

Yup. This tells me the AWU is not the adventure watch for me. I love my Apple Watch (8? I think?) and I love my Garmin Instinct Solar with 40d battery life. One of these is for daily wear as a communicator; the other is for weeks in the mountains or offshore.

Hyperbole is Apple’s favorite communication style, but at this point it’s so overused that it’s just a meaningless meme. Apple’s wearable competitors blow the Apple Watch’s battery life out of the water and it’s not even close. Hyperbole is all Apple has in this race.

On the flip side, Apple blows them away on feature set, and often on data accuracy. There is give & take, different priorities for different people.

Blows them away? I haven't seen anything that is not just one or two features that other watches don't have. But all the.features require the watch to be on.

Data accuracy most certainly is not in relation to GPS which often cuts distances on the Apple Watch.

People like to complain about the GPS but I use it when running and it'll easily show me what side of the path I was on at any given point. And the path distance matches precisely with other sources of truth. Maybe there was a time when Garmin had an advantage on some of their watches but I am far from convinced that this has been true anytime in the past few years.

To be pedantic it's not just GPS anymore. Newer smartwatches from Apple and competitors generally support multiple GNSS constellations including GPS (USA), Galileo (EU), GLONASS (Russia), Beidou (China), and QZSS (Japan). Some devices also support multi-band GPS which further increases accuracy in areas with degraded satellite signals, although at the cost of higher power usage.

Tracking performance on the previous Apple Watch Ultra 3 was "solid" in an independent test. A little worse than competitors in some activities, a little better in others.

https://www.dcrainmaker.com/2025/11/apple-review-ultra-3-in-...

I’ve had a previous Apple Watch Ultra, it was nice but after playing with it for a while I used it for notifications and working out. I have a Garmin Epix Pro Gen 2 51mm that will do 31 days of being just a smartwatch and can track my multi day cycling trips. The real killer feature I didn’t know I needed until I had it is a proper led torch on my watch, the light up screen on the Apple Watch doesn’t compare.

I need to see receipts on this claim. 31 days as just a smartwatch would be a stretch. Tracking activities also during that time, based on my experience with many, many Garmin watches, would be a bridge too far. My EpixG2 will last 7-10 days, with 1.5-2 hours of daily workouts during that span. I have most power hungry features turned off, like always on display, pulseox monitor etc.

In any case, it’s longer than the AWU by a long way.

Isn’t Apple famous for faking GPS accuracy by moving the points to roads and paths using their mapping data?

I bought an Apple Watch recently so I can enter my workplace without much hassle (first world problems). Highly disappointing watch coming from a no-name Amazfit brand. I like my step counter, I don't care whether it's slightly off, I want to see it on my watch face - you'd safely assume it was possible, but no! So now I have to go through multiple menus and swipes to see it and it doesn't even show right away (takes several seconds at times). Don't get me started with the joke that is the battery life.

Apple Watch is probably Apple's shittiest product today.

I take it you are opposed to using non-Apple apps? I show step count on my Apple watch face.

No, I'm not opposed. I got my watch like 2 months ago and haven't really messed with it since. Just baffled that the option doesn't exist. Which app do you use for that and does it affect battery life?

Why so helpless? Maybe try and solve the problem before complaining about it.

Pedometer apps that pull from Apple Health and offer Watch face complications are a dime a dozen in the app store.

Users just find it odd that this isn't a built-in optional data field considering that step counting (pedometer) has been one of the most common smartwatch use cases for many years now.

First the complaint is that steps are not on the watch face. Then the complaint moves to it not being part of Apple's built-in complications. It seems more like nitpicking just to be contrary. The data is there and easily accessed for people who want it, and we should be happy that there are a plethora of third-party complications that can be used on the Watch.

Having basic expectations out of a smart watch isn't being nitpicky.

What's it matter if I solved the problems then complained about it after? The bottom line is the battery life is garbage and not including a pedometer as a complication is silly.

Check out Pedometer++

Thanks, will do.

The battery life during workout tracking did at least see a 3x improvement. 14 hours sounds plenty at first until you start riding your bike over long distances! 45 hours should cover most except the craziest ultra athletes, and those are probably sponsored by Garmin anyway

I haven't met anyone who is serious about cycling and not using a real bike computer.

Triathletes are more likely than most cyclists to use wrist computers over bike computers.

(Cue joke about triathletes not being serious about cycling.)

If anything triathletes are least serious about swimming

Fair enough, but they are not really cycling for 45 hours :)

If biking around 5000 km yearly is serious enough then I'm one - using only my phone to track. Since I will be taking my phone with me anyway, I don't need another device.

My Garmin Venu 4 has 10+ days.

My Garmin Fenix has over two weeks with regular activity tracking. Wish people were more aware of these amazing devices.

My Casio F91W has 7+ years. AW are much more capable devices than Garmins, both when it comes to compute and screen - it's understandable they use more power.

Meanwhile, 2-3 weeks on my Pebble Time 2

Meanwhile, 7 years on my F-91W

Why do you need it to last longer than ~20 hours?

It’s very convenient not having to worry about your watch state of charge.

Dear Apple,

I want to send you my money, but your expensive watch I want to buy is f**ing massive and my wrist is normally sized. I don't really understand why this is still an issue since it's been 4 years.

Thanks,

- Guy with slightly below average wrist circumference (40th %ile)

An "Ultra Mini" with a proper lap button would open my wallet very quickly.

Same, I’d pay for more physical buttons

I just want the extra (vs non-Ultras) button THAT'S ALREADY THERE to allow mapping to "lap". Blew my mind that wasn't possible when I went to try one at the apple store.

LOL @ downvoting this of all things.

Isn't that what it already does if you have the action button set to "workout"?

Not that I could find in settings... the settings menu let me start a workout but that was all I saw. Maybe it just wasn't discoverable... Just looked at the online user manual and the only mention of lap control is in the stopwatch app (not workouts). It does mention secondary actions, but doesn't elaborate... if that actually does control the lap, Apple really sucks at doc.

:shrug:

Plus, I really want a mini version. The Ultra is MASSIVE to the point it's ridiculous.

I’m probably 60% and would feel ridiculous wearing one.

The 4th generation heart rate sensor is quite interesting -- Apple Watch used to sample every ~5 minutes, and now it's every 5 seconds (basically continuous). I think that'll enable a lot of interesting health & wellness use cases.

It's interesting because during workouts, the heart rate sensor samples every 5 seconds but besides that, it was either every 2 or 5 minutes. I'm guessing the battery drain is too much to have it sample every 5 seconds all the time!

Too bad Apple reserved the [training] Readiness feature only for the Ultra 4 - I'm pretty sure Ultra 3 and probably below are just as well equipped to provide such insight...

non ultra apple watch has it too

Had this thought during the presentation. How is the “rewind” feature legal? Don’t a lot of states have laws against making secret recordings?

Recordings, yes, but this is transcription.

It doesn't save a recording of someone speaking; it's 15 seconds of a transcription.

My understanding is it’s E2E transcribed dictation via PCC? Is that not the case?

I guess it was already technically possible with phones though, or hidden tape recorders for something more old-school. Not sure on the legality.

They made it very clear that it doesn't record anything.

If it doesn’t record anything how does it make a transcript? I think some of these laws are strict enough such that no audio recording, even if it’s immediately discarded, is legal.

But of course, I am not a lawyer.

People generally don't think of keeping bits in memory for some short period of time as "recording".

Doesn't stop it being...recording, though.

There are similar exceptions. For instance, the copy of licensed content that your computer makes in RAM in order to play it is explicitly exempt from being treated as a copyright violation.

isnt that how the modern telephone system works? digitize your voice, encode, transmit, decode, convert to analog audio. with buffering or keeping bits in memory all along the way?

is a telephone call a recording?

and taken to it's extreme.... isn't the atmosphere secretly taking the vibrations in the air right outside out mouth and propagating them through a physical medium, making them available to anyone to capture?

An audio "recording" is data (digital, analog, grooves on vinyl, whatever) that allows later listening to the original audio.

What Apple is doing in Rewind is as legal as if you were to take a contemporary transcript of a conversation. That's not illegal.

It's legal even if you're a skilled shorthand transcriber and get every word. That's Rewind, if I've understood it correctly.

You've always been allowed to transcribe (ie, write) out a conversation. Recording is a different thing. A person can always claim, easily and believably, that the transcription is made up. It's just text.

Is that the main differentiator? Not the use of a microphone to create the transcription?

From a legal perspective you can't record something in many us states. Using the microphone, keeping the bits in memory while you turn it into text, probably doesn't meet any reasonable definition of "record".

Maybe this will be true legally (we wont really know until it is tested in court), but I think there's a huge difference in practice.

Siri Recap is an electronic record of a conversation that includes timestamps. Imagine for example that during a scheduled meeting with my boss, he threatens to fire me for not doing something illegal. I now have strong evidence that this was said (even if it cant be officially attributed to him) during the time I was in a meeting with him. Not saying this will hold up in court, but it certainly is more damning that having written notes (not to mention the fact that my boss probably wouldn't say this when I am taking written notes).

Yup, and maybe the law will need to evolve.

Fwiw, imo, you should assume everything you say (and write) is recorded going forward.

Making that feature illegal may backfire spectacularly across the whole IT sector. What Apple does is it inputs voice data into an AI program and that outputs some transformed output. If a court would rule that output in any way matches the input (to be classified as a "record") then the whole ethics principle of stealing other people's data and funneling it through AI to make it company's own, would be at risk.

I imagine no single spineless impotent modern court would risk a wrath of our new benevolent AI overlords calling them all criminals they really are.

There was an app that hit it’s peak during covid: Clubhouse.

Many powerful and interesting people were having powerful and presumably private conversations in rooms because they say people walk in and out and legally CH could not record without consent. But what they could do was “collect metadata”. Emotional and tonal analysis is metadata. So is time, date, location, username (each user had their own mic stream), email, etc. Transcription is also metadata.

Essentially the tech has left the laws in the dust as you could now reasonably and legally record enough metadata to accurately resynthesize a recording.

The only thing keeping on a Garmin is that my OG AW Ultra probably won't last a mountain 50 miler (I've used it for easier 50 mile races). If it truly lasts anywhere near 45 hours, even my old, slow ass could knock out 100 miles in that time.

Plus satellite comms on the AW (which I'd have to spend money to upgrade the 965 to get that feature). I just might pick one up next week.

"A batter you can't outrun" actually the gen 1 Pebble from literally 2013 still runs circles around this thing.

I recently got their new gen Pebble Time 2 and this thing lasts about a month on a single charge!

The battery life boost doesn't seem all that big relative to the Ultra 3, certainly not big enough to warrant upgrading.

[Dupe] https://news.ycombinator.com/item?id=49631121 - this one seems to have more lively discussion

So apparently Siri AI is not coming to my part of the world anytime soon because of EU law. With that, I see no reason at all to upgrade from my Ultra 1, as not much else has improved in any meaningful way in 3 years. Don't get me wrong, I love my Ultra 1. But I had hoped for more innovation in three generations of it.

Not because of eu law. Because Apple wants an exception to the rules.

They don't get it. Malicious compliance. So many credible proofs of them doing it, but people still rather be apologists for a trillion dollars company.

Because Apple wants an exeption to the ridiculous and insane rules the EU has imposed on their citizens. EU is sooo irrelevant, sooo behind in tech... And such laws only worsen the situation.

When are they going to detect blood sugar?

When the patent trolls die down and accuracy improves.

Huh, this "Readiness" innovation seems really similar to the "HybridCharge" my Amazfit watch has had for a couple of years (but obviously at literally 10x the price, but you do whatever you want with your money, chaps...)

It's surprising that in 2026 they still haven't figured out how to remove the bezels. They are smaller than they used to be, but On something as compact a watch, all screen estate counts.

As someone who often backpacks off grid, the features listed are pretty interesting. Anyone have any alternative products this competes with? The "adventure" watch is a new thing for me

Not to be too dismissive, but have you heard of Garmin, Suunto, Coros, or Polar? They all have something similar.

I have heard of Garmin, but neither of the others so they must have a more narrow marketing reach. I will review their product catalog and see how the value compares. I could have an agent go scour the web for product recommendations and substitute products, but I enjoy the discourse and perspective on HN so I like to ask here.

As a user of both Garmin (and Suunto, Coros, Polar would be in the same category) and Apple Watch Ultra, you'll find one main difference again and again: battery life. The not-Apple-watches will last a week or more before charging, AW will make it a day or two.

OTOH, as far as a smart watch goes, AW will be head and shoulders better. For me, it's a lot of little cuts with Garmin. For instance, setting a timer for my tea is like six button presses on the Garmin, and that's with a shortcut keypress to get to the timer. AW: there's a complication on the watch face, one press. Or, "Siri, five minutes". Three presses otherwise. I haven't owned anything from the other brands in a long time, so can't comment on the likes of Suunto or what have you.

Some will tell you that AW is "okay", but "serious athletes" use a Garmin. Meh, whatever. I've got a running resume as long as my arm, and I just preordered the AW Ultra 4 to replace my Garmin (and my AWU 1). AW gives me the data I need, and it will last long enough for me to get through a 100 mile race, so I won't miss much from Garmin. And good $DEITY, Garmin's prices are getting ridiculous. $1200 for a titanium Fenix? I don't care how long the battery lasts, that thing better wax my fucking car.

If you want to save a little money, I've heard nothing but good things about Coros.

> For everyday use, Apple Watch Ultra 4 now offers more than two days of battery life, up to 50 hours.

This is the reason i don't like these smart watches... I always forget to charge the watch.....

You just plug in your devices when you go to sleep. I don't get why that is difficult.

That does diminish the sleep tracking benefits. It's still doable, but now it becomes "remember to charge your watch at least an hour before bedtime" which isn't as simple of a routine.

Hmm okay I haven't though about that.

If you’re using the sleep tracking features, the watch will remind you if it thinks it won’t have the juice to get through the night.

15 mins of charging during a shower is usually all I do for my S9

That was fine until I started using it for sleep tracking. Now it’s kinda hard. I put it on the charger when I’m taking a shower and having dinner still it’s not super convenient.

Two days is so poor for a ultra watch. The fact it won't last a full weekend let alone any significant hike just means it doesn't fit the market it is aiming at.

A weekend? How about a full week at the absolute bare minimum, if not more.

3 days is a complete joke. Competitors have battery lives measured in weeks rather than days (a famous, and still 100% appropriate, quote by Garmin. Now 5 years old and counting, and the situation is still as ridiculously bad).

Seriously what is it even doing to justify going through the battery so fast? Are they just bad at programming?

I completely agree with you, I was just trying to avoid being attacked by a certain group. I assume it's the processor as it isn't designed specifically for battery life etc.

So no new sensors. No blood pressure or glucose (very long shot) monitoring. I was holding out for the blood pressure monitor but I will have to wait longer now.

Having Garmin Enduro with 3+ weeks of battery life seems funny to watch apples ultra ads ...

I've owned multiple generations of Apple watches before and the battery life made me ditch it. After about a year, the watch wouldn't even last a full day with mostly passive usage.

I'm considering trying Ultra just so the battery can comfortably last full day without entering power saving mode by 8pm.

Disappointing to see Apple doesn't consider battery life to be a major problem. They keep balancing efficiency and battery gains with new features consuming more juice to keep battery life roughly the same as the previous generations.

With the readiness feature - I think they are trying to close the gap with Garmin.

I bought an Ultra 3 and was quite disappointed with it. The heart rate monitor frequency is really low. I'm glad to see they have at least fixed that. I dual-wield right now with a Fitbit Air to supplement the data.

The battery life being so short is just pathetic. My Garmin can last up to two whole weeks in a similar form factor and its pretty much the only differentiation

$800 for a watch.

Man we lost it as a society.

Others are not able to eat, die because of insulin prices, struggle every day and we sit here on HN and people are thinking about buying the next gadget.

A watch for $800...

Insulin shouldn’t be expensive. What’s that got to do with high-end smartwatch pricing?

It's more a comment about what we value as a society. An Apple watch is an utterly optional accessory that nobody needs. And yet there's a bubble of rather wealthy people who will buy them without really giving it a second thought, and another large group of people who really can't afford one but will buy it anyway.

And? People buy what they want to buy. Apple builds what people want to buy. Been like this forever.

And? Why do you even the comment on a social critisism comment? Just ignore it, feel happy when you buy yourself the next stupid thing while you feel offended seeing your fellow citicen.

Why does it even trigger you then?

It doesn't trigger me, I'm trying to understand why it triggers the other guy. Now, pass the baton.

There's also a bubble of wealthy people who spend their time commenting on HN articles, complaining about .... other wealthy people.

For what purpose? Virtue signaling?

Man that’s so deep - some people are purchasing things while other people cannot purchase said things.

Society is so screwed :/

The social critisism is, that people in the united states of america (were apple is home), let people die while also buying unironically $800 watches as a mass consumer product.

Insulin isn't expensive. Walmart sells 100 doses for $77

You do understand that this was headlines for years? Did you complelty ignore that?

It only got 'fixed' 2023 and insulin still costs $30-50 per month for something you need to live.

And you do realize that the press was talking about an entirely different insulin? A long lasting injection which isn’t 100 year old formula. The price of insulin has been the same the entire time

But the old insulin is a lot harder to manage and we know why the 'normal' insulin became so expensive. Greed

I'm referencing us american people who were unable to afford insulin due to us americans shitty healtcaresystem.

Search for Alec Smith in Minnesota.

Its social critic, you did not get that? A country which let their own people die but also make such a product.

How much of your networth have you donated to the starving people? Nature is pretty metal and doesn't care about justice. I thought we all learned this in school.

This is not an apple fan club. Someone likes it and comments, i use it to bring up a comment like this.

Just don't deflect.

Btw. i'm from a country with a social system soooo

I understand the sentiment, but you can spend a lot more than that on a watch if you want to, and for a watch that does a lot less. Few people do though, and a lot of people will probably buy the Apple.

You do realize people have been paying tens of thousands for watches for decades, right (and for hand bags, sunglasses, necklaces, rings, etc)?

$800 is not particularly egregious.

And?

Is this an apple fanboy club and critisism is not allowed or you don't think this critisim is valid because of your strawman argument?

you are allowed to criticize apple as much as you like. The response was on your 'really? 800 for a watch' remark.

watches that go for 100k or more are not uncommon

Yes but these watches are hand made from clock makers and a homage to real craftmanship done mostly by human hands, well paid, well educated.

And these companies are old, they were leading in chainging the world.

Apple let them build in china from students and others for very little money with very high margin.

Rolex for example is a foundation.

> Rolex for example is a foundation

This is not true. rolex is a for-profit organization. The owner is a foundation, but they did not make rolex a non-profit.

Sorry to inform you about Patek Phillipe:

https://www.watches-of-switzerland.co.uk/Patek-Philippe-24-H...

Yes, you're correct, billionaires should not exist, and we should keep raising taxes until that is true. The "real" max wealth number is probably a bit lower, but 10 digits of wealth is a good starting point.

“Wealth” isn’t just shiny things you buy, beyond a certain point it’s mostly the amount of the economy you control.

I’m curious how you propose that business ownership should work?

This is not a consumer product but a homage to craftmanship and clearly a luxury product.

Apple is a mass produced product under shitty work conditions.

Glancing at Richard Mille watches and thinking... $800, peanuts.

If my grandmother had wheels she'd be a bike

How can you possibly make that comparison

Maybe she's on a wheelchair. One is a watch and another one is a watch. Both show time. How could I not.

> die because of insulin prices

Where does that happen? Even without insurance in America insulin is like 25 bucks a month.

Minnesota in 2017, when you search for Alec Smith.

A tragic case, and maybe things were different back then. Now, Lilly caps their insulin out-of-pocket costs at $35/month, insurance or not. Walmart has cheap no-insurance insulin, too, I'm not sure if that was true in 2017 though. Alec was trying to ration a much more expensive insulin variant, which definitely sucks, and laws were changed in response to his story.

Josh Wilkerson

And it wasn't just a case.

And i'm not allowed to reference this?

I mean i can reference a lot of other things which are still happenin in the USA or do you know want to argue that united states of america takes good care of its people?

> do you know want to argue that united states of america takes good care of its people

I'm not downvoting you, but perhaps the people who are are taking issue with cherrypicking examples, which are well known for a reason -- they are uncommon. Using these to generalize America is not really a great argument.

I could point to David Clapson in the UK as an indictment of their universal health care, and it wouldn't be any better an argument.

Walmart has had cheap insulin for decades, and update their formula periodically as patents expire. Not many know about it, though. I've used it when traveling and it works even though it's not as effective as the current prescription insulin.

I mean how often do you buy a watch? Compare with how much do you spend on groceries every month...

We can have real arguments, but lets be clear, comparing a $800 dollar watch you use for lisening to music and paying is not the thing to compare to something you actually need to live.

worse when you pay 100k+ for a watch you can only use to ... read the time (the patek watches that were mentioned earlier for example)

There is the non ultra series and SE series.

What are you talking about?

Interesting but the short battery life and 40m (130ft) scuba diving depth limit still make it useless for me.

40m diving is more than good for a lot of divers. I am allowed to go on a 30m dive and that’s probably at the 75 percentile of divers.

Looks like you'll be one of the only people using dive watches for their actual purpose then.

There are dozens of us!

130ft/40m is standard limit for non-tec diving.

Past that depth, you will be using diving computers and not a smartwatch. And the training you receive will help you to understand why.

Who is "you"? I have the training and sometimes go significantly deeper. I use a competing Garmin smartwatch, works great. Do you understand why?

How deep are you going? What gas mixtures are you using? Which Garmin are you using? If you're using a Mk3i or a G2 (or related) you are using a diving computer in a smart watch form factor. It is custom built for this... unlike the Apple Watch Ultra.

I'm still using the older Garmin Descent Mk2 model, which is basically equivalent to the Mk3 for diving features. (I might upgrade to the Mk4 when it launches later this year.) It sure is handy to have a single smartwatch that can do everything.

We use a variety standard breathing gas mixes for the depth range based on limits imposed by density, narcosis, decompression time, and oxygen exposure.

You go significantly deeper? You're aware that shortly past 50mt the partial pressure of oxygen causes neurotoxicity, leading to convulsions and death? Anything happening past those depths involves extremely expensive hardware, custom trimix breathing gases and most importantly a hell of a good reason to even bother doing it - that is NOT the environment for an Apple Watch.

Yes, I go significantly deeper. You seem to be a little confused about how oxygen toxicity works but rest assured that we're aware of it and use appropriate breathing gasses for the depth.

I understand that an Apple Watch Ultra can't be used for those dives, and that's fine — they don't need to support every possible niche use case. But competing smartwatches from Garmin and Suunto do handle deeper dives and the associated gas mixes. There's nothing stopping Apple from doing the same if they want to.

> You seem to be a little confused about how oxygen toxicity works

Thanks for the condescending tone. Am I?

At 1.4 bar of O2 partial pressure (therefore, with a 21% breathing gas mixture, at around 66m depth), oxygen toxicity causes convulsions and unconsciousness. If someone doesn't grab you and take you up, this likely results in death.

Btw I had to google the precise values and depths to be accurate, but I'm not talking out my ass. I'm a certified CMAS and AOW diver with 80ish logged dives. Hardly a veteran but this was in my certification course and it's a very real thing - enlighten my confused state with your better knowledge please.

You're talking out your ass and unclear on the basics. Obviously we're using standard gas mixes based on the depth profile, not compressed air. For the working portion of the dive we generally limit PPO2 to 1.2 atm but will go as high as 1.6 for portions of the deco. If you'd like to understand diving physiology instead of just repeating what you Googled then Bennett and Elliott is a good place to start.

https://www.us.elsevierhealth.com/bennett-and-elliotts-physi...

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