The set of 4 pool pillows is the ultimate companion and cover for any pool during winter. It keeps your pool covered safe from ice in the winter months because it keeps water off of your pool cover. The pillow also ensures your cover does not freeze to your pool water during the cold off-season. This pillow is made of sturdy PVC, making it durable for outdoor use. When inflated, each one measures 110 x 110 cm big. It pushes your pool cover up off the water's surface so the water won't freeze to your pool cover.