This was also my question, and I found what seems to be the answer. It's not quite definitive enough for me, but it's the best I've found so far.
> Note: it’s 60fps epaper, not off the shelf Eink. We spent years developing what we think is the best epaper display in the world and it’s exclusively manufactured by our display factory in Japan.
> Note: it’s 60fps epaper, not off the shelf Eink. We spent years developing what we think is the best epaper display in the world and it’s exclusively manufactured by our display factory in Japan.