thorlos St Mountaineering Thick Padded Over The Calf Sock 60% Wool, 27% Acrylic, 11% Nylon, 2% Spandex Made in US No Closure closure Turn Inside Out-Machine Wash-Use Liquid Fabric Softner Fiber Contents: 60% Worsted wool, 27% Exclusive THORLON acrylic, 11% nylon, 2% spandex Thorlos clinically-tested padding under the ball and heel provides maximum protection from friction, the Primary cause of blisters, and impact protection where needed most Performance Fabric: Constructed with thermal worsted wool and THORLON fibers for superior softness, resilience, durability, and moisture-wicking for drier, better feeling feet Made in Statesville, North Carolina, USA 30 Day Guarantee: Thorlos feel better than ordinary socks. If you do not agree, send the socks and your receipt to Thorlos for a full refund.