In The Swim 8 Mil Swimming Pool Solar Blanket Cover 20 x 40 ft. Rectangle 8-mil thick solar blanket constructed with reinforced flat seams Thousands of tiny air bubbles work to transfer solar heat into your pool Reduces chemical loss through evaporation, saving time and money on chemicals and rebalancing Can be easily cut or trimmed to fit kidney, oval or irregularly shaped pools Backed by a 3-Year Limited Manufacturer's Warranty