Exclusive Wool/Silk Blend for maximum warmth and wicking. Moderate cushioning in ball/heel for shear protection and comfort. Thin cushioning in shin protects from boot pressures; flat knit instep and arch for better fit and ventilation. Fiber Contents: 32% Wool/THOR·LON®, 32% Wool/Silk, 20% Stretch nylon, 13% Olefin, 3% Spandex