21' Round Ultra Premium 25 Year cover. This is our best winter pool cover and its tough as nails. This solid winter cover is designed to fit 21 ft round above ground pools. With the 4 ft of overlap actual cover size measures 25 ft round. This cover features a commercial grade 14 x 14 scrim count and the heaviest coating in the industry. The cover has a polypropylene cord sewn into a double stitched hem, is fully bound on the edges by commercial grade material and is made with UV inhibitors to prevent damage from the sun. The cover is brown on the top side and the black underside helps to prevent algae growth. Included are a vinyl coated steel cable along with a non-rusting deluxe aluminum cable winch for secure lock down. 2 non-rusting aluminum grommets every 3 feet for added strength and security. 25 Year warranty with 3 year full rated.