I'm honestly not sure if these are intended as slippers or shoes.  I wear them as shoes.  They have a suedey insole that feels like memory foam, and a thin, flexible sole.  They're flexible, almost socklike, right out of the box.

One caveat is that they're pretty long.  (I think it's telling that I wound up lending them to someone who's almost a foot taller than me.)  If I could reorder them, I'd try at least half a size smaller and perhaps a full size smaller.