Extend your hot tub season and reduce water evaporation with our 7-ft x 8-ft Rectangular Solar Blanket. To optimize heat retention, this blanket has an opaque, blue color that allows the maximum amount of sunlight to reach the water. Thermal bubbles retain that warmth even after the sun is gone, keeping your spa water warm even on cloudy days and cool nights. This innovative technology can increase your hot tub’s water temperature up to 15 degrees Fahrenheit. Backed by a 90-day warranty, this blanket is designed to withstand direct sunlight and harsh conditions.