This Robelle Premier Supreme Plus oval solid winter cover features a 12 x 12 Scrim count (threads per square inch) and a material weight density of 3.7 ounces per square yard. The Slate Blue topside has been treated to inhibit damaging ultraviolet rays. A black underside prevents the growth of algae. Made of polyethylene, this exceptional quality above ground winter pool cover has a 4-ft overlap, allowing the cover to be used on above ground pools with top rails up to 9 inches wide. There are 2 grommets approximately every 4 feet for the use of a cable to secure the winter cover. A plastic-coated cable and winch are included. The overall size of this cover is 20'W x 29'L. It is designed for oval above ground pool. All Robelle Supreme Plus winter pool covers come with a 18-year warranty.