In-Ground 12-mil Solar Blanket Cover - Our solar blankets are made to give you the maximum heating and insulation properties, combined with long life. Durable 12-mil blankets are loaded with thermal bubbles that retail heat at night and on cloudy cool days. Our transparent blue color helps insure that the sun's heating rays are reaching your pool water. Your pool will be up to 15°F warmer than an uncovered pool. All our blankets are U.V. protected so they last under the most intense sunlight. They are backed by a 5-Year Warranty.