All our socks are made by SOS in Colorado, and feature CoolMax CoreSpun fibers to wick moisture away from the foot quickly, providing an excellent defense against blisters. We put the CoolMax on the inside of the sock where it belongs and the nylon on the outside to provide lasting durability. The cuff uses Lycra for a truly gentle, supportive ankle band. For colder conditions, check out our high quality wool socks.