The newer ones at least (only Oasis used to have it before followed by PW4).
I use the PW4 beach/poolside. Works super great under direct sunlight. Plus, I got mine for $65 during mother's day sale with Amazon Prime CC cash back so not a big loss if something happens to it.
Feels like the PW4 on 5.10 has shorter battery life compared to my PW3 on 5.9, though.
I wanted something lightweight, waterproof and with 64GB storage (my book collection after ten years is 30GB, so 64GB seems safe long-term).
Unfortunately, only the Scribe has 64GB, but its not waterproof. Plus, its not really lightweight, about as much as an iPad 11.
Hate to say it, but my iPhone is still my best ebook reader.