Swim Central 20' x 40' Jet Black Closing Deluxe Leaf Net Cover for In-Ground Swimming Pools The Super deluxe winter cover is made with extra strong laminated polyethylene material with thick, The Super deluxe cover is silver on one side and black on the other and will prevent algae growth all The cover has metallic grommets and comes with a cable and ratchet to securely fasten it over the top rails