The Aggressor Sock 3.0 is the warmest of KLIM&';s men&';s riding socks, designed to keep your feet warm while wicking moisture. Made of a Teton Merino Wool blend, these durable socks enhance the performance of KLIM&';s waterproof, breathable footwear to keep you comfortable in extreme conditions. Great for riders with cold feet looking for thicker, warmer socks. 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) Made of European sourced yarns 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 Tubular cuff for better fit & stretch recovery Over-the-calf height SM = 4-6, MD = 7-9, LG = 10-12, XL = 13-15