In the Swim 12′ X 24′ Premium Blue Rectangle Solar Pool Cover 12 Mil for Solar H
Thickness 8 Mil 12 Mil 16 Mil 8 – 12 Mil 8 – 12 Mil. Heat Retention & Solar Warming: Harnesses the power of the sun to naturally warm your pool water while helping retain heat overnight, extending your swimming season without increasing energy costs.