Wrightsock Men's Fuel Lo Single Pair Socks Inner: 70% Polyester, 26% Nylon, 4% Lycra; Outer: 68% Polyester, 24% Nylon, 8% Lycra 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