The variable flow regulator : Important : The pressure prevailing in the flow regulator is always equal to that distributed by the steering governor. Description : It is composed of : 1) a body, 2) a piston sliding in the body, 3) a barrel, with a calibrated hole, sliding on the central section of the body where the small ports are drilled. 4) a spring R acting on the barrel 5) a valve and its spring.