Healthy Walk mens socks are made from two materials. These have white cotton on the bottom and black regular sock material on the rest of the sock. The white part is supposed to be good for preventing fungus. They come in two sizes. Size 6-12 is for about size 4-7 shoe and size 13-15 is for about a size 7 and larger shoe. These are 80% cotton, 18% lycra, and 2% nylon.