The feeling is like they're made of paper, which I guess they are. Having just played some bongo drums with regular leathery heads I now realise there is a world of difference between getting these papery bongos vs. getting just the cheapest "real" bongo drums.
Also, beware, these don't fit older Thomann bongo drums anymore even though the description says they do! The size of the smaller drum has changed since a few years back when I got the Thomann bongos.