Durable materials and the innovative design featured in this Robelle Supreme Winter Pool Cover provide peace of mind through winter while you patiently await the return of summer. The cover was constructed from a strong polyethylene material that won’t rip thanks to its durable weave, which features 12 vertical and horizontal threads per inch. The topside of the cover is colored green and has been treated to prevent damaging ultraviolet rays, while the underside is strategically colored black to prevent algae growth. Water bag loops are double stitched and spaced four feet apart with aluminum grommets that ensure maximum reinforcement. The premium winter cover comes with a 12-year warranty.