The standard diaphragm material is a combination of the PTFE on the wetted side backed-up with FKM for strength and flexibility. Body made of Natural Polypropylene. There are no metal parts in the wetted areas. The miniature air-operated diaphragm valve that performs like a heavyweight. Designed for pressure and drain applications with highly corrosive or ultra-pure liquid systems when space is critical. The valve is ideal for a broad range of industrial applications, from electronic to chemical plants, commercial laundries, car wash operations, etc. For applications with ultra-pure water and concentrated etchants, such as in the semi-conductor industry, it provides the ultimate in non-leaching, contamination-free sealing. The standard valves are air pressure to open with spring return to close. There is no minimum inlet pressure required. Not designed for vacuum service. Normally-closed operation. A 3-way air solenoid valve connected to the 1/8" NPT port is required to actuate the diaphragm valve. When air pressure is applied, the diaphragm valve opens and when removed spring force closes the valve. The standard valves are precision machined from the highest quality brand thermoplastic bar stock with female NPT connections. It is recommended that filtered, lubricated compressed air be used. The cylinder head features multiple seals, in addition to the main diaphragm seal in contact with the liquid. There is a vent located between two seals (above the main diaphragm, below the cylinder head u-cups) that will "weep" in the event of a primary seal failure. The valve will still function, under pressure, without metal contacting liquid. This is the patented Plast-O-Matic Fail-Dry, which adds an additional layer of "protection" for your process.