"What kind of battery is inside?

Index 01 uses silver-oxide batteries.

Why can’t it be recharged?

We considered this but decided not to for several reasons:

You’d probably lose the charger before the battery runs out! Adding charge circuitry and including a charger would make the product larger and more expensive. You send it back to us to recycle. Wait, it’s single use?

Yes. We know this sounds a bit odd, but in this particular circumstance we believe it’s the best solution to the given set of constraints. Other smart rings like Oura cost $250+ and need to be charged every few days. We didn’t want to build a device like that. Before the battery runs out, the Pebble app notifies and asks if you’d like to order another ring."

Uhhh... Huh... Ok. Welp, that's a nope from me then.