Teton Merino Wool blended w/ acrylic, Polyamide Nylon, Lycra, SoftAir Polyester for durability & comfort (36% Merino Wool, 31% Acrylic, 12% Nylon, 17% Elastane, 4% Polyester) Reinforced toe, heel, sole Full Terry Loop construction for cushioning and warmth Arch & ankle support stretch bands Patterned front mid ankle bend for reduced bulk KLIM Women's Solstice Sock 3.0. Sizing - Women's SM = 5-6, MD = 7-9, LG = 10-12.