The ultimate American Sock is a bison sock from United by Blue. Made completely in the US from ranched bison fiber, these socks are superior for warmth and comfort. Tapered to fit the foot, plush looped interior to capture body heat. Great for winter boots, hiking, fishing, hunting, or anywhere you need a hearty sock to get you through. 64% Merino Wool, 17% bison down, 16% nylon, 2% polyester, 1% spandex. Two sizes to choose from: Large / Men's 9 - 12 , Women's 10-13. Small / Men's 5-9, Women's 7 - 10 . USPS Priority Shipping included in price.