Petra's 11.5 Ft. x 11.5 Ft. Woven Waterproof Terracotta Square Sun Shade Sail.Petra's shade sails are the most cost effective shade solution per square foot and the perfect outdoor shade sail for your backyard or patio area! Also known as Sun Sails, shade sails make beautiful additions to your patio, backyard, or other outdoor areas, while providing excellent protection from the sun and its harmful UV radiation. Shade sails are wonderfully versatile; they can be attached to homes, fences, trees, or patio columns. In addition, they can be supported by wood posts or steel columns embedded in concrete footings. They can easily be taken down seasonally if necessary. Shade sails are the ultimate in stylish sun protection.The heavy duty Polyethylene weave allows rain to pass through, so there is no pooling water. This unique state-of-the-art mesh material will block up to 90% of the sun's UV rays, while "breathing" to allow air to circulate and keep the environment underneath much cooler.The perimeter of each sail is designed with a gentle centenary curve inwards toward the center of the sail to control the fabric tension. Our shade sails have reinforced webbing around the perimeter, and steel D or "Delta" rings at each corner. When properly tension-ed, shade sail fabric will not wrinkle, sag, or flap in the wind. The woven polyethylene material will keep you cool and out of the hot sun. This unique state-of-the-art material will block the sun and UV rays, and will withstand damages caused by moisture and natural temperature extremes. Washable with regular soap and water. Heavy duty design will not droop or sag and completely durable through all seasons.