This durable 30x50 foot rectangular in-ground solar blanket is made to give you maximum heating and insulation properties, combined with long life. This 12-mil blanket is loaded with thermal bubbles that retain heat at night and on cloudy cool days. The transparent blue color helps ensure that the sun"s heating rays are reaching your pool water. Your pool will be up to 15° warmer than an uncovered pool. Blanket is U.V.-protected so it will last under the most intense sunlight and backed by a 5-Year Warranty.