"This Northman in-line adjustable flow control valve is designed to restrict the flow of oil in a hydraulic system to control the speed of a cylinder or motor. The flow in one direction is metered as adjusted. The flow in the opposite direction is full free flow over a check valve. Port Size in. 3/8 NPT, Max. PSI 3,000, Max. Flow GPM 8. In-line mount Metered flow in one direction, full flow in opposite direction"