Supreme Plus Round Swimming Pool Winter Cover Green/Black-with Cover Clips (21 Ft. Round) This super tough cover has a 4-foot overhang 12 x 12 scrim per square inch. Double grommets every 3 feet. Double Stitched & thick hems using UV resisted nylon threads. Reversible Green/Black color. Ultraviolet light inhibitor to protect against the suns damaging rays. Pool Cover: 21' Round Cover Size: 25' Round. Comes with 32 Cover Clips