The Bridgedale Mediumweight Knee Storm Sock is made with Merino Wool which provides comfort & warmth throughout your outdoor adventure &, thanks to the additional terry-pad sections, offers supple cushioning in the ankle, heel & footbed. Designed to offer a close fit & arch support, the outer nylon fabric adds a protective barrier around the waterproof membrane, designed to safeguard your foot & leg from wet ground & any knee-high water hazards, such as rivers & streams, while the long-length cut ensures additional protection from the rain & extra coverage of warmth. Specifications Outer: 95% Nylon/ Polyamide, 5% LYCRA®/ Elastane Inner: 54% Merino Wool, 36% Polyester, 7.5% Nylon/ Polyamide, 2.5% LYCRA®/ Elastane Membrane: 100% PU Glossary Merino wool is a fine, very soft, natural fibre that is excellent at regulating the body's temperature. The hollow fibres are very light & trap in lots of air, perfect for insulation, & retain warmth when wet. Merino wool is also very breathable, wicks moisture away from the skin, & has natural antibacterial properties that combat body odour.