The anti-microbial military boot sock made to USOA specs is 82% cotton, 2.5% silver plaited nylon, 10% nylon, 5.5% spandex. The silver fiber incorporated in this sock is a broad spectrum anti-microbial yarn that actually touches the skin, kills bacteria on contact, completely eliminates all foot odor, offers enhanced blister resistance, moisture transportation, temperature management, and anti-static features. Three pairs to a pack. Sizes: Small 9-11 Med 10-13 Large 13-15