Sealskinz Unisex Thick Weight Mid Length Trekking Sock Nylon / Elastane Thick weight, mid length sock for a multitude of activities where added insulation is imperative Totally waterproof, breathable and windproof Merino wool lining for moisture control & comfort Elasticated ankle & insteps offer support and a comfortable fit Material composition: 91% Nylon, 9% Elastane; Hydrophilic Membrane; 42% Merino Wool, 40% Acrylic, 16% Polyester, 1% Elastodiene 1% Elastane