Sure-Flex KEE PVC utilizes DuPont® Elvaloy KEE, a resin modifier that results in permanent flexibility, increased UV resistance and improved long-term weathering. Elvaloy eliminates the need for a lacquer coating, which may be effective initially but loses its resistance to dirt and microbial growth over a short time. Sure-Flex KEE PVC is ideal when the roofing membrane will be subjected to harsh chemicals and conditions like acid rain, grease, air-conditioning coolants and intense sunlight.