Our Wool socks and arm warmers are made from 75% TURBOwool, a superior blend of 50% polypropylene and 50% Merino wool, which provides five times the strength and durability of Merino wool alone. Shrink-resistant and itch-free, these socks will keep feet dry and warm in all weather conditions.Our wool socks feature:a Superior wicking and durabilitya TURBOwool deluxe wool blend is 5x stronger than Merino wool alonea Year-round performance: warmer in winter; cooler in summer