Socks made by Conscious Step help people, animals and the environment. The purchase of each pair works with a partner to help the environment. Each pair of Socks that Plant Trees plants ten trees through Trees for the Future. These are size medium which fits USA Men's 8-13, USA Women’s 9-14. The socks are made of 75% Organic Cotton, 23% Polyamide, 2% Spandex and have a seamless toe. Machine wash warm and lay flat to dry.