Liquids original design of using an innovative non-air-permeable construction blocks wind, glare and airborne irritants from interfering with your vision. Its speed-drying fabric overcoat quickly wicks away moisture. The insert is a thermal barrier using thin polycarbonate sheet material with an anti-fog coating. The clear panel works just like a ski goggle lens and separates hot from cold to prevent condensation. This product invention has not changed since it was developed many years ago by the founder Rock Wilson. Customers say this product has lasted longer than any other product they have tried.