Fangrui Product Details Protect Your Pool During All Winter: Our Pool Pillow Creates Tension Which Effectively Protects Above-ground Pool Walls And Pool Covers From Pressure Caused By Expanding Ice. This Prevents Expanding Ice Along Side Your Pool Walls. Designed To Withstand Cold Winter: This 4 Ft Winter Pool Pillow Is Made From Ultra Strong , Cold- Pvc Material. It Provides Plenty Of Support And Material To Last All Season. Great Protection: Air Pillow Absorbs Freezing Water As It Expands. Relieves Above Ground Pool Walls From Stress Of Ice Expansion. Helps Reduce The Build-up Of Rain, Leaves Or Snow On Your Winter Cover. Staying In Place: Just Slip The Included Rope Through And Tie The Pool Pillow To Your Pool And The Reinforced Grommets At 4 Corners Around The Pillow To Keep The Pillow In Position At The Center Of The Pool. Inflate Deflate Easier: We Chose Double Fold Valve, Which Allows Inflating And Deflating Much More Faster Without Lossing Of Air. Works Seamlessly With Most Blower. Foldable , Easily Roll It Up To Stor