WESTMAN Steel's Tough Rib Poly-Lite and Ridge-Lite Skylights and Sidelight panels bring natural light into buildings. These panels retain optical clarity, meaning that they won't yellow like fiberglass. These products are made of tough polycarbonate and are up to 20 times stronger than fiberglass. Tough Rib Poly-Lite and Ridge Lite panels are 100% UV protected, as well as hail and wind resistant. Tough Rib also withstands extreme temperatures, from -40°F to 270°F, to match the performance of the most popular metal roofing profiles on the market today.