The 653B features a high speed motor and gear/driver assembly to provide a fast response to a given set point to quickly achieve desired pressure and increase system throughput. High accuracy is attained by microstepping the flapper to give more precise control, and no drift, of pressure at the desired set point. The 653 has sufficient torque to operate sealing valves up to four inches and non-sealing valves to 12 inches to prevent clogging from contamination build-up.