Blue Waves 8-Year Solid In-Ground Winter Cover is made from durable polyethylene with a 7x7 scrim count. This cover is designed to protect your pool from winter elements and prevent water from passing through. Heat-sealed seams are reinforced for added strength and the cover s black underside helps to ensure a clean pool in the spring. It features a generous 5-foot overlap for a proper fit. Integrated loops are spaced every four feet to secure water tubes and reinforced corner grommets allow for extra security. Water tubes are sold separately. Backed by an 8-year warranty with the first year fully covered.