Sun2Solar Blue 20 ft x 40 ft Rectangle Pool Solar Cover | 8 Mil | Heat Retaining Solar Blanket | Heats Rectangular Inground & Above Ground Swimming Pools | 800 Series Includes 6 Heavy-Duty Grommets

From the brand

Free Solar Energy: This solar pool cover uses the sun’s power to raise water temperature by up to 15 Degrees
Traps Heat: Our pool solar cover retains warmth long after the sun sets, helping to maintain consistent water temperature overnight
Conserves Water: By reducing evaporation up to 95%, this swimming pool cover helps cut back on chemical use and the need for additional water.
Debris Prevention: Stops leaves and debris from entering pool, reducing maintenance and keeping your swimming pool clean and clear
Easy Installation: Our pool covers for above ground and inground pools have a durable design with extra overlap, making it simple to install and remove while fitting around any protrusions (trim as needed).