The all Polypropylene construction of these true union ball check valves eliminates rust or corrosion issues.  This ensures that the valve will never stick, jam or fail to operate like a metallic valve might due to corrosion.  The True Union Ball Check Valve is rated to 150 PSI at 70°F.  The "True Union" enables you to remove the valve from the system for maintenance without disturbing piping connections.  Viton seals and seats are standard (EPDM is an option) and designed to be compatible with aggressive fluids.  The full port design ensures maximum flow at a low pressure drop.