The Ariat Marl Thermal Socks are made from a blend of Wool for superior warmth, Acrylic for superior softness, Nylon for rugged durability and Lycra Spandex to hold everything securely in place. These are toasty warm boot socks perfect for hard-working feet in cold weather climates and conditions. Wool Blend Yarn Superior Wicking Two Pack Rugged and Durable Cold Weather Boot Socks Ariat Marl Thermal Socks, AR2296-029-M