The winter round above ground **pool cover** is a laminated polyethylene sheeting woven with thick, high density polyethylene stitching which ensures superior tensile strength and durability. All covers are treated to provide maximum resistance to damaging ultraviolet rays to inhibit deterioration and increase longevity. Above ground pool covers feature a ratchet and cable system featuring high test vinyl coated cable.The **Swimline** Air Pillow will keep your pool and cover safe from ice in the winter months. The pillow helps to keep water off of your pool cover, why also helping to make sure your cover won't freeze to your pool water.1 Buy = 1 Pool Cover + 3 Air Pillows