This durable 21x41 foot oval above-ground solar blanket can warm your pool by up to 15°. It is made to give you maximum heating properties combined with long life. This 8-mil blanket is loaded with thermal bubbles that retain heat at night and on cool cloudy days. The transparent blue color allows the maximum amount of solar rays to reach your pool for optimal heating. The blanket is U.V.-protected so it will last under the most intense sunlight. Built to last and backed by a 3-Year Warranty.