100% Acrylic Outer: 100% acrylic yarn that doesn’t absorb water. Dries quickly and doesn't feel heavy when wet. Membrane: Micro-porous membrane allows vapour to escape but prevents water from entering Inner: 100% polyester fleece to keep your head warm and comfortable. Thermal to insulate the head but not so hot that your head sweats. Windproof to retain as much heat as possible between the fleece and your head. OTTER 100 Percent Waterproof, Windproof, Breathable - Beanie Hat Ideal for Walking Fishing. OTTER Waterproof Windproof Breathable Beanie Hats Suitable for All Activities in All Weather Conditions Caps in 7 Colours - B0IV4GPZH