Lorpen Women's Tri-Layer Medium-Weight Overcalf Sock women's trilayer medium over calf ski sock - specific fit for women Trilayer knit technology layers both synthetic and natural yarns in a way that improves moisture management, comfort and durability 50% Primaloft Eco Polyester yarn, 25% merino, 15% nylon, 10% lycra Primaloft blends 50% virgin fibers and 50% recycled fibers to create a high loft performance insulation. high lycra content keeps socks wrinkle free and in place