21' Round Leaf Net Winter Pool Cover 21 ft Round- 4- YEAR Manufacturer's Warranty Leaf Net Tight mesh traps even the smallest leaves before they reach your winter cover. Made from durable woven polyethylene and carries a 4 year warranty. Extra 3-foot overlap and include a cable and winch to hold it securely in place over your winter cover. Black mesh fabric. * Other brands of leaf nets have larger mesh that allows small leaves to pass through to your winter cover and decompose in the spring.