Bought these to wear with a suit. I wear men's size 8 and bought medium. Outside of the package, I was a bit frustrated with the top two buttons not snapping on my ankles. They are made of vinyl material with no stretch panels. I put them on a towel and heated them with a hair dryer until they were warm enough to stretch out and put them on, along with the shoes I was about to wear and a pair of thick socks. I wore them until they were cold and now they fit perfectly!