No they usually use Kaleido. They don't specify but it matches with the poor color saturation and 4096 colors.

Kaleido is a b/w eink panel with a colour LCD overlaid.

There's tech that looks much better like eInk's ACeP (much stronger color saturation) but it needs multiple flashing refreshes to update so it's not feasible for interactive devices. They're just being marketed for advertising and the like.