Rectangle Super Ring - Heavy Duty, Super Durable Sun Shade Sail | 5 Colors & 12 SizesShadeMart Rectangle Super Ring Shade Sails are the most durable shade sails on the market; they are made of 260 GSM permeable HDPE (high density polyethylene) fabric with cable wires built into edges and integrated into our patented steel mounting corners Cable wires relieve the strain from the weakest part of shade sails, the fabric, ensuring years of reliable service Provides dense 98% shade coverage and 95% UV blockage Reduces ambient temperature