The 2-stage pump can give you faster cycle times and higher possible pressure with a small engine. Excellent for use on log splitters. 85% efficient. U.S.A. Max. PSI: 3,000, Shaft Diameter (in.): 1/2, Shaft Type: Straight keyed, GPM: 2.9, 13.6, Stage: 2, Material: Cast iron, Usage: Open center hydraulic systems, Rotations Per Minute: 3,600, Weight (lbs.): 10