Extend your swimming season with our 18ft/5.49m solar pool cover. It helps raise water temperature and retains heat overnight. Made from durable 16 mil PE material, it reduces evaporation by 95%, minimizes refill needs, and keeps your pool clean. | Vevor | | Solar Pool Cover, 18 ft Round Pool Bubble Cover, 16 Mil Pools Solar Blanket with Bubble & PE Material | Blue | Best Buy