This is the strongest winter pillow in the market. Our winter pillow are the only winter pillows that come with a full one year replacement warranty. This pillow is designed to stay inflated all winter. This pillow has two layers of material. An inner PVC material to inflate and an outer Poly material to protect it. No other winter pillows are made like this. This pillow will protect your pool from ice over the winter. If this pillow does not hold air over the winter for any reason we will replace it for free for the first year.