Direct link to that image (webp?): https://media.npr.org/assets/img/2022/09/08/hat-2_wide-6ae40...
WaveCel, the manufacturer highlighted by NPR, has a detail page about their technology: https://wavecel.com/technology/
They published a Biomechanics paper about this: https://doi.org/10.1007/s10439-021-02723-0
Bontrager’s WaveCel material more effective at preventing concussions than MIPS (2019) https://news.ycombinator.com/item?id=20825502
The most valuable paragraph I found there to keep in mind when considering around WaveCel and/or MIPS is:
> So far it does seem that measuring impacts at an angle matches real world brain damages better than the older standards of measuring dead-on impacts. That's what "rotational acceleration" means. Acceleration is just another word for impact. It doesn't mean your skull should rotate freely.
(I have no stance on MIPS or WaveCel beyond that.)
But after I bought it I recall seeing articles that undermined the claims. I know they have one or two good papers showing efficacy, but I think it's not quite settled science at this point.
As far as I can tell it’s just an extra layer of thin plastic that sits, unattached, under the expanded foam.
The idea being that it slides and stops the helmet gripping you head.
I’ve often wondered, how much of the same feature would be achieved with just a cycling cap under the helmet?
I’m not sure there was a huge premium for getting MIPS so I guess I’m happy to have it. It certainly doesn’t hurt.