"Brand Hydraulics side-ported adjustable flow control valve will start or stop a hydraulic cylinder or motor and vary speed over wide range. Once set, maintains constant speed regardless of load variation. Excess flow is returned to tank or used to power another function. Port Size in. 3/4 NPT, Max. Flow GPM 30, Max. PSI 3,000. Adjustable relief preset at 1500 PSI Internal relief valve"