This Swimline SuperGuard In Ground Pool Cover is perfect for keeping your 20 x 40 foot pool in pristine condition during the winter months, and it will also make getting your pool back into shape in the spring much easier! In ground pool covers help prevent wind blown dirt, debris, and leaves from entering your pool, so you can get back to swimming with less hassle and in less time.This in ground pool cover has been treated to provide maximum resistance to damaging ultraviolet rays to help it resist deterioration and increase longevity. It's made of laminated polyethylene sheeting woven with thick, high density polyethylene stitching ensuring superior tensile strength and durability.Protect your pool during the winter with the Swimline In Ground Pool Cover.