SockGuy's wool line of socks are made from itch free TURBOwool which is a blend of 50% Merino wool and 50% polypropylene. By doing a blend of natural and synthetic materials SockGuy is able to make a sock that is 5 times stronger than that of a pure Merino Sock. SockGuy wool socks are shrink resistant and machine washable for easy care. Merino provides natural moisture wicking, is antibacterial, and provides all season comfort.