DexShell Waterproof Trekking Socks Large 24% nylon Mid-calf length merino wool athletic socks Porelle membrane prevents water from passing through Merino wool reacts to your body's temperature, keeping you warm when it's cold and releasing body heat and moisture when it's hot Seamless construction for the highest comfort, Cushioned footbed Perfect for trekking, hiking, camping and other long-range activities Outer: 96% Nylon, 3% Elastane, 1% Cuff Elastics Interlining: 100% Waterproof and Windproof Porelle(R) Membrane Inner: 38% Merino wool, 38% Anti-pilling acrylic, 24% Nylon Mid-calf length Seamless construction for the highest comfort Cushioned footbed Small -  Men 4-6     (Women 5-7) Medium - Men 6.5-9   (Women 7.5-10) Large -  Men 9.5-12   (Women 10.5-13) XL -    Men 12.5-14.5