GLI Pool Products HyperLite 20-2040RE-HYP-GRN-S-AC 20' x 40' Green Rectangle Safety Cover. If you open your pool in the late spring, have large amounts of leaves and debris in the yard and require the strongest and lightest solid safety cover available - this is the cover for you! Another staple in our stellar collection, this arm of our solid cover options are not only secure, but they are also 30% lighter than standard solid covers and each comes standard with our distinctive Commercial Grade Springs on Custom Covers.