Koss Industrial, Inc. sells the Type E Main Valve, which is a pressure reducing valve. The Type E Main Valve is a self operated, external pilot type, single seated, metal diaphragm actuated, normally closed designed valve. The internal parts of the valve consists of the seats, discs, stems & diaphragms, which are constructed of stainless steel. There are no springs in the steam space and there is no stuffing box. A major bonus of this valve is that the Type E Main Valve is easily maintained. All of the valves parts are accessible without the valve needing to be removed from the line. Pictured here is the Type E Main Valve with a D Pilot mounted on to it in order to regulate pressure.