The HIKING XTRA sock was developed as a lightweight outdoor sock. This sock provides Double Layer protection in a medium weight ideal for all seasons. Feet stay dry as the CoolMax wicks the moisture away from the foot and into the outer layer for evaporation. Blisters are prevented as the layers move slightly to absorb friction. This is a great sock for lite weight hikers, approach shoes, adventure walking and other casual footwear when maximum cushioning is not required. . Fabric: Inner Layer 70% CoolMax®, 30% Nylon Outer Layer 72% Solara Acrylic, 4% Lycra®