It is used to regulate the oil in one sense and have the full flow on the opposite one, it is not pressure compensated so the setting depends on the application pressure, the oil viscosity and the oil temperature. The range includes sizes from 1/8 BSPP (1/8G) up to 1-1/2 bspp (1-1/2G). This version does not have the external thread for nut tightening. Setting is made by knob rotation clockwise and vice versa. Once the valve is set, tighten the lateral nut placed on the knob to lock the setting. It does not allow leakages. The external body is made of high resistance steel and externally protected from oxidations by zinc treatment. On request we can supply a zinc/nickel treatment to increase the oxidation resistance when the valve has poor protection or it is located in external environments.