Extend your hot tub season and save energy with a 7-ft x 8-ft Solar Blanket. This rectangular spa cover traps heat from the sun and effectively raises the temperature of your spa. Made out of 12-mil polymer, this blanket can increase water temperature up to 15 degrees Fahrenheit and out-performs comparable Intex spa and hot tub covers. The transparent blue color allows the maximum amount of the suns rays to reach your spa for optimal warming. Innovative thermal bubbles retain heat through cloudy days and cool summer nights. UV-protected and chemical resistant, our blankets are designed to withstand years of direct sunlight.