Red Maple's Alpaca Copper Crew has heat reflecting Copper fibers that help relieve symptoms of stress & aging – perfectly enhancing the warm, luxurious softness of Alpaca. Colorgrown Alpaca & Cotton (no dyes used) are organically produced & blended with Copper, then knit with Nylon & Lycra for shape. Machine washable & dryable. It’s a great everyday sock on its own, a dress sock, or excellent as a layering sock under a heavier boot sock. Available in Unisex sizes Medium and Large. Medium fits Women's shoe sizes 7½ - 9 and men's shoe sizes 6-8½. Large fits Women's shoe sizes 9½-10½ and men's shoe sizes 9-11½. Colors available: Oat, Hickory, Granite, and Silver