Thorlos Unisex EXCOU Extreme Cold Thick Padded Over the Calf Sock 60% Worsted Wool, 26% Acrylic, 11% Nylon, 3% Spandex Turn Inside Out-Machine Wash-Use Liquid Fabric Softner Padding Level: Maximum Cushion Key Benefit: Maximum Protection = Maximum Comfort Guarantee - Your feet will feel better or your money back! Proudly MADE in the USA | North Carolina 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 Worsted wool provides warmth while THORLON Acrylic wicks any moisture away from your foot because a dry foot is a warm foot Unique padding specifically designed for extreme cold weather activities Ventilation panel extra moisture control and breathability