I bought these on the spur of the moment because my feet hurt while I was out. I only used them that day. I haven't used them since. The heels show no wear and tear, and they are in beautiful condition. The upper part is made of a stretchy, knit-like material that doesn't hurt and is easy to walk in. The size is listed as M. They fit me perfectly, and I wear a 23.5 cm size. I will pack them as small as possible for shipping.