Dexshell Hytherm Pro Waterproof Socks 20% nylon Imported Mid-calf length merino wool athletic socks Porelle membrane prevents water from passing through Merino wool it 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 Easy care with either hand wash or machine wash below 40C