This unit is a direct action, screw in, catridge style, spool type, hydraulic 3 Way, 2-Position. Directional shuttle valve,which may be used on a hydrostatic transmission to direct charge pump oil to heat exchanger or tank. HOSV - Is a hot oil shuttle valve, spool type springless without relief HOSR - Is a hot oil shuttle valve, spool type springless with relief Specifications: Operating Pressure: 5,000 PSI (350 Bar) HOSV Flow: 23 LPM to 60 LPM HOSR Flow: 22.8 LPM Valve Housings: 2,500 PSI (210 Bar) = Aluminum 5,000 PSI (350 Bar) = Steel