Parker Series D*FH is a high response, proportional servovalve with an on-board drive amplifier.

High Frequency Response — The valve has a very high frequency response which is necessary for many closed loop applications.  Four Position Spool Capability — The four position spool provides predictable flow in the event of a power failure to the drive electronics, within the limits of the power curve. The maximum operating pressure rating for the D*FH and D*FM is 315 Bar or 4500 PSI (Port P, A, B). Plus  10 and - 10 command and +/- 20 mA Command Input