900GS (Globe) and 900AS (Angle) Series are Stainless Steel, full port, dual chamber basic valves that incorporate a one-piece disc and diaphragm assembly. When pressure is applied to the upper diaphragm chamber and released from the lower diaphragm chamber, the valve travels to a closed position. When pressure is applied to the lower diaphragm chamber and released from the upper diaphragm chamber the valve travels to a full open position. When pressure is balanced between the upper and lower diaphragm chambers, the valve will hold an intermediate position until commanded to modulate open or closed by the pilot control system. Stainless Steel construction provides superior corrosion resistance, a lightweight alternative to conventional heavy iron valves, extended diaphragm life, and reduced frequency and labor costs associated with traditional maintenance repairs.