Wallaroo Waterproof 2m X 4m Outdoor Sun Shade Sail Canopy Rectangle The above shade sails not only offer the highest sun protection but are also manufactured from waterproof polyester fabric, enhancing their durability and longevity. High-density polyester, offering up to 95% UV block out, marine-grade 316 stainless steel 8mm D rings on every corner, UV stabilized stitching on the perimeter of the sail, and not to mention, webbed edgings in conjunction with reinforced double stitching. Note: Shade sails need to be installed at 30-degree angles to ensure that water does not pool in the middle of the shade sail, resulting in deterioration.