The Z Cloud sandal by Chaco is an innovative and original design featuring a SINGLE STRAP passing through a single layer sole. It takes some attention to detail and time to properly adjust the strap to your foot, and at first I struggled to find a balance of firm medial arch support that didn't pinch my little toes. But with practice and perseverance I came up with this sandal. That's a brilliant idea. I remember casually chatting with my little brother about the development of the single strap sandal, but wondering if it would really be possible to develop a working system. Well, the Chaco design team did it. And here's the icing on the cake: I have flat feet like a goose. After using these sandals for about two weeks, my ankles and arches are really improving, even walking or standing barefoot. BRAVO to the design team at Chaco and many thanks to the manufacturers. I recommend these sandals to my brother and people I know.