Teton Merino Wool blended w/ acrylic, Polyamide Nylon, Lycra for durability & comfort (36% Merino Wool, 31% Acrylic, 11% Nylon, 22% Elastane) Reinforced toe, heel, sole Engineered Terry Loop for strategic cushioning and warmth Arch & ankle support stretch bands Patterned front mid ankle bend for reduced bulk KLIM Women's Solstice Sock 2.0. Women's Sizing - SM = 5-6, MD = 7-9, LG = 10-18