The Swimline 4 x 15-Foot Air Pillow is the ultimate companion to any winter pool cover. This Swimline air pillow will keep your pool and cover safe from ice in the winter months because it helps to keep water off of your pool cover. The pillow pushes your pool cover up off the water's surface so the water won't freeze to your pool cover, helping to prevent damage to your pool cover during the during the cold off season. When inflated, it measures 4 x 15 feet big. Keep water off the top of your pool cover and prolong your cover's lifespan with the Swimline 4 x 15-Foot Air Pillow. We are an Authorized Swimline Swimming Pool parts dealer!Swimline is a family owned and operated business founded in 1971 and is the leading manufacturer of high quality pool products. At its inception, Swimline was the largest manufacturer of in-ground and above-ground pool liners, covers, and all related accessories.