These ultra warm socks are 90% Australian Merino wool. They are heavy knit and perfect for wear under a tough work boot or in winter to keep toes warm. They have a wool terry sole for warmth, softness and comfort. One size fits most. 90% Merino Wool, 8% Polyester. 1% Nylon, 1% Elastane. Short warm wash on medium cycle. May be tumble dried on warm. Do not bleach. Do not professionally dry clean. Do not iron.