El Naturalista leather slip-ons

Cool black leather slip-ons from ever-funky El Naturalista. Made in Spain. Leather lining. They have obviously seen some love: this is really only evident, though, in the dark marks on the footbed. Outside black leather and soles are in great shape. (Speaking of which, who knows what those soles are made of; note the 'recyclus' on the bottom.) Also I should note that, at least on my feet, the straps so not sit tightly, esp on the right shoe. Doesn't affect wear but just a heads up. Size 38; I would say they fit like a 7-7.5.