KLIM Mammoth Socks Gore-Tex 100% terry construction for added warmth and padded comfort Ankle and arch support stretch band to help keep sock in position, no slipping or bunching Above calf height for warmth and comfort 43% Merino Wool, 40% Acrylic, 13% Lycra, 4% Polyamide *Note that the use of a technical sock is required to obtain the full functionality of Gore-Tex boots.