Hi-Tec Light Weight Hiker Crew Sock merino-wool 75% Merino Wool, 22% Nylon, 3% Spandex Merino Wool aids in moisture management, Arch Compression secure sock around the foot to reduce sagging, Ribbed Leg conforms around the leg helping to keep sock in place, Welt Top work injunction with rib leg to hold socks up, Reinforced heel & Toe for durability and comfort Machine wash inside out in warm water, no bleach. Tumble dry low. Do not dry clean USA