Thorlos Anti-Fatigue Men's and Women's Over-the-Calf Socks 84% Thor-Lon Acrylic, 10% Nylyon, 6% Elastic Turn Inside Out-Machine Wash-Use Liquid Fabric Softner 82% Thorlon Acrylic,9% Nylon,5% Spandex,4% X-Static Exclusive Thorlon construction for resilience, durability and better wicking Sock size 11 fits Men's shoe size 5.5-8.5, sock size 13 fits shoe size 9-12.5 and sock size 15 fits shoe size 13-15 Moderate cushioning in ball/heel for reducing shock, impact, shear and blisters Flat knit at instep and thin cushioning in the arch improves fit