This Robelle Super rectangular solid winter pool cover features a 8 x 8 Scrim count (threads per square inch) and a material weight density of 2.36 ounces per square yard. The Imperial Blue topside has been treated to inhibit damaging ultraviolet rays. A black underside prevents the growth of algae. Made of polyethylene, this exceptional quality in-ground winter pool cover has a 5-ft overlap, allowing the cover to be secured with water tubes on the pool deck. There are grommets located on each of the four corners of this cover. The overall size is 30'W x 55'L. It is designed for a rectangular in-ground pool. All Robelle Super winter pool covers come with a 10-year warranty.