Thorlo Unisex Thick Cushion Running Crew Sock 2-Pack 88% THORLON Acrylic, 10% stretch nylon, 2% spandex Extra THORLON provides a maximum fitness density padding for better durability, protection against shock, impact, and shear forces These socks are unisex sizing, please see sizing chart under images or under product descriptions for sizing. Lightweight padding in arch provides arch support and a better fit Thorlo Running Socks