This unit is a pilot operated, sliding spool, screw in cartridge style, hydraulic pressure reducing valve. PRPS - Is a pressure reducing device for secondary circuit. PRRS - Is a pressure reducing/relieving device for secondary circuit. Specifications: Operating Pressure: 5,000 PSI (350 Bar) PRPS Flow: 46 LPM PRRS Flow: 23 LPM to 91 LPM Valve Housings: 2,500 PSI (210 Bar) = Aluminum 5,000 PSI (350 Bar) = Steel