These durable, Made in USA, fully Berry compliant socks are USAF certified Safe to Fly. They provide all the warmth, comfort and features needed in a high performance environment, with the added safety and assurance that your feet will be protected by our flame resistant and certified "no drip no melt" technology. Unisex fit URfit® System provides arch support and memory-knit construction Cushioned sole absorbs shocks and insulates Multi-filament yarn construction makes it very abrasion resistant and adds durability Smooth, flat comfort toe seam 70% Merino Wool, 20% Nylon, 8% Nanonglide® Nylon, 2% Spandex Style #6064