The original Sealskinz 100% waterproof mid length sock featuring Hydrostop which is the perfect barrier for use in wet and warmer weather conditions. Waterproof - three layer construction for warmth, durability and waterproofing Comfort - Bamboo lining for moisture control, insulation and comfort Hydrostop - Reduces water ingress Support - zonal elastication for added support Comfort - flat toe seams prevent rubbing Hydrostop - SealSkinz Hydrostop technology creates a seal between the sock cuff and skin, helping to reduce the amount of water from running down the leg and into the sock MaterialsOuter: 94% Nylon, 6% Elastane Membrane: 100% Polyurethane Inner: 75% Bamboo rayon, 23% Nylon, 2% Elastane