[Designed to Withstand Cold Winter Temperatures] Pool pillows for above ground pools are made of ultra-strong, super durable, 0.24mm thick, cold-resistant PVC material. Designed to withstand freezing temperatures, this pool pillow can handle cold as severe as -12°C. [Pool Winter Pillow Size]: 4' x 4' Pool pillows for above ground pools are built to withstand cold winter temperatures, it is designed to distribute the pressure of ice freezing to help your pool walls. [Easy to Inflate and Deflate]: The pool winter pillow features a unique, double Boston valve, which allows for 10x faster inflation and deflation compared to valves. Works seamlessly with most. Foldable, easily roll it up for storage. [Protection for Your Pool All Winter] The pool winter pillow with sealing technology and embossed, cold-resistant material, means it won't leak, break, or deflate during winter. Inflate the pool pillow to 60-70% of full capacity so that, as freezing progresses, the impact of expansion goes to pressing the pillow against the walls. It can protect above ground pool walls and pool covers from pressure caused by expanding ice. [Stays in Place] The pool cover pillow is designed with 4 reinforced grommets in the corners to keep the pool pillow in place in the pool - Just thread the included 2x16.5 ft long rope through and tie the pool pillow to your pool. color: blue Material: PVC Package Contents: 1 x Pool Pillows 2 x rope Only the above package content, others are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.