Wrightsock Men's Fuel Lo Single Pair Socks, Black, Sock Size:10-13/Shoe Size: 6-12 Inner: 70% Polyester, 26% Nylon, 4% Lycra Spandex; Outer: 68% Polyester, 24% Nylon, 8% Lycra Spandex Machine Wash Two layers trap air for effective insulation from heat and cold Improved moisture management Interaction between layers absorbs friction and prevents blisters Maximum comfort Guaranteed blister free