.Air Pressure 30 psi, Stroke 4 in, Nominal Spring Range 8 to 13 psi, Mounting Type Pivot, Net Force Exerted @ 0 PSI 88 lb, Net Force Exerted @ 18 PSI 55 lb, Length 20 1/2 in, Width 4 3/4 in, Height 7 1/2 in, Provides Gradual or Positive Actuation of Dampers, For Use With Medium to Large Dampers, Includes Pivot Post and Mounting Plate Linear Pneumatic Actuator, Operating PSI Range 8 to 13, Max.