FlexAirâ?¢ ISM Disc Integral Saddle Mount : Glass-fiber-reinforced polypropylene construction formaximum chemical, temperature, and UV resistance. â?¢ Premium quality membrane materials available: EPDM,silicone, urethane, PTFE MATRIXâ?¢. â?¢ High-capacity membrane option available for maximum airflow and low operating pressure. â?¢ Triple-check valve design minimizes entry of liquid/solids into piping. Ideal for on / off applications. â?¢ Integral Saddle Mount provides ease of installation and maintenance with maximum mechanical strength. â?¢ Mounts on any pipe material (PVC, ABS, CPVC, SS, etc.) â?¢ 12â?� disc available to fit 3â?� and 90 mm pipe sizes; 9â?� disc available to fit 3â?�, 4â?�, 90 mm, and 110 mm pipe sizes â?¢ Patented EZ-Sealâ?¢ for quick membrane installation