- Jil sander's new thick-heeled slippers are a shoe that gets better and better the more you look at it. The design is as simple as ever without losing the sense of fashion. It's full of retro style, unique and handsome! A must-have item for summer! Upper: cowhide, lining: sheepskin, heel height: 8cm, sole: Italian genuine leather outsole, size: 35-39 (40 is custom-made and cannot be returned or exchanged),