Interchangeable motor spool. Adjustable relief. Enclosed handle design. Open center – field convertible to power beyond and closed center. Low spool leakage (3 cc/min @ 1500 PSI). Hardened steel spools. Spool Seals In Internal O-Ring Grooves. High Pressure Adjustable Relief Adjustment Range 2000-3500 psi (Preset To 2500 psi @ 6 GPM).