You can't go wrong with these socks from Dan Post! Featuring an advanced design, this work sock outperforms ordinary work socks. The reinforced heel and toe features Endurall« friction reduction design. Made of 85% acrylic/5% SORBTEK« A.M.Y.«/5% FYnesse« Endurall«/2% polyester/3% Spandex. Medium size fits men's shoe size 7 -10 and large size fits men's shoe sizes 10 1/2 -13.