The Pool Mate Sandstone Above-Ground Pool Cover protects your pool during harsh winter conditions. This professional-quality, polyethylene cover blocks out any dirt and debris throughout the winter. The Sandstone cover prevents algae growth by blocking UV rays from entering your pool. Pool owners who use a Pool Mate Sandstone Pool Cover and close their pool with the proper winterizing chemicals will have a clean pool in the spring that will be easy to open. It is always recommended to open your pool by mid to late May. This cover features a 4 ft. overlap making it easy to install. Grommets are placed every 4 ft. and should be used with the included cable and winch. This high-quality, lightweight cover with heat sealed seams is built to last longer. The Pool Mate Sandstone Above-Ground Pool Cover comes with a 12-years warranty.