Blue 21' Round Above Ground Pool Cover + 4' x 8' Air Pillow + Winterizing Kit Pool Size: Fits 21' Round Pools U.V. Inhibitors Protect the Cover From Sun Damage 3 4 Foot Overlap (cover size is 3 4 ft larger than pool size) Highly resistant to punctures, tears, chlorine stains and other chemical stains 7x7 weave