content: The largest size I've ever worn is 8M (stilettos, flip-flops, athletic shoes, flats, etc.) from varying brands. According to Injinji's Web site, size small fits up to size 8 shoes in women, but it is short, causing a very snug, somewhat uncomfortable fit. As a result, I've only worn them once to exercise. I was worried that they may slip underneath but they did not. However, the fit and whether or not they will stay in place is definitely not a good thing. They also came out fuzzy in the wash. I'm keeping all six because the inconvenience of returning them to Amazon is too much.