Air Pillow 4 ft x15 ft allows you to protect your above ground pool's walls from damage caused by changing water pressure during the winter months. Installing easily underneath your winter cover, it also prevents your leaves, rain and snow from accumulating on top of the cover and collapsing it. Its 16-gauge vinyl construction is thick enough to handle freezing temperatures with ease, and resists leaks better than cheaper alternatives. Best of all, Blue Wave Air Pillow 4 ft x 15 ft is priced to fit into anyone's budget, making it perfect for any above ground pool.