This durable 30′ Round Above Ground Solar Pool Cover Blanket can warm your pool by up to 15°F. Measuring 8-mil thick, this solar cover pool blanket is loaded with thermal bubbles that retain heat at night and on cool cloudy days. Its transparent blue color allows the maximum amount of solar rays to reach you pool for optimal heating. The 8-Mil Blue Solar Cover is U.V.-protected so it will last under the most intense sunlight and is backed by a 3-year N/A.