This 4’ x 4’ air winter pool pillow will spread the pressure of the ice against the walls of your above-ground pool and prevent damage. It also prevents snow or rain from accumulating in the center of the pool cover and causing it to collapse. It is made of premium cold-resistant vinyl, that can withstand low temperatures of -10° F (-25° C). It can be quickly inflated with just an electric inflator. A double valve allows inflating without the loss of air. It is recommended to inflate 60% to 70% of the total volume to allow expanding ice to squish the pillow rather than push against the pool walls.