The Sealskinz Waterproof Knee Socks have been made with a 3 layer bonded contruction, with a 100% waterproof hydrophilic membrane and a merino wool interior that works to keep you warm as well as having sweat-wicking properties. They are knee length to keep your whole foot and lower leg protected from the elements.3 layer bonded construction100% waterproof hydrophilic membranePremium merino wool interior for warmth and sweat-wickingDurable nylon blend exterior4-way stretchSeamless construction with flat toe seamsElastic support on ankle, heel, instep