Our HLGP is a 2-stage hydraulic gear pump. It offers a large displacement at low pressure and a small displacement at high pressure. The transition from low pressure (preset at 650 psi but adjustable) to high pressure (maximum pressure is 3335 psi) is automatic to meet load requirements. These pumps are perfect for log splitters, trash compactors or any other applications where rapid movement of the cylinder at low pressure is required prior to automatically switching to the high pressure mode to meet load requirements.