In-ground pools can be kept secure through the oftentimes harsh and destructive months of winter with this Robelle Dura-Guard Ultra Winter Cover. The cover includes a five-foot overlap and is available in various sizes, while its gray top is made from high-density, UV-resistant polyethylene. The bottom side of the cover comes in a strategically-colored black – the dark shade prevents dangerous algae growth. Another key feature of this pool cover is its high-quality binding, which covers the entire perimeter, keeps grommets in place, and adds to the overall life-expectancy of the product. High-strength water bag loops are stitched every four feet for additional security and the winter pool cover comes with a 20-year warranty.