Polyflex cap sheets are premium, polyester reinforced APP modified bitumen roofing membranes specially designed for heat-welded applications. Constructed with premium Atactic Polypropylene resins, and incorporating superior polyester reinforcing, Polyflex provides an exceptionally durable roofing product which is easy to install and will provide long-term weathering performance. With a smooth surface and either a polyolefin or sand backing, Polyflex exceeds all minimum ASTM standards for tensile strength, puncture resistance and flexibility. Polyflex membranes can also be used as flashing membranes in all applicable specifications, in accordance with recommended installation practices.