Zensah Copper Running Socks 43% Nylon/21% Copper Nylon/16% Merino Wool/11% Polypropylene/9% Spandex Imported Cushioned heel and toe: the running Copper socks feature a cushioned heel and toe to help prevent blisters and minimize impact while running Superior breathability: a Special mesh design around the top of the foot provides an advanced ventilation System to keep feet at the optimal temperature Anti-odor and moisture wicking: Copper yarn blended with merino wool helps to wick away perspiration, keeping the socks light and dry No-Slip cuff: a no-slip cuff prevents the Copper socks from slipping or sliding into running shoes, ensuring they feel great mile after mile No blisters: a flat seam in the toe of the Copper socks helps to prevent blisters and chafing, as well promote ultimate comfort