Measurement is taken from corner to corner, edges are made slightly curved based on precisely calculated radian, prevent shade sail from sagging in the middle for best appearance and performance. The shade sail is made of virgin polyethylene and has strong tensile strength, and light weight. It provides up to 95% UV blockage and 90% visibility blockage Shading, cooling, ventilation in the summer, anti-frost in the night, slightly rainproof during the rainy season. Perfect for outdoor areas, backyard, driveway, carport, swimming pool, garden, patio, balcony. 3-Year Limited Warranty All of our products are available to be customized. We make custom size