The check valves with leakages of the VS series are recommended in every condition where a restricted flow is needed in one direction, while the flow must be free in the opposite one. Free flow is granted by a mobile ball which open the way to oil; the same ball close the way in the opposite direction and the oil is diverted through fixed restrictions which determine the leakage. Two different sizes of restrictions are available for two different leakages. The valve hasn’t any hydraulic compensator: the leaking flow is so variable according with the pressure drops across the valve. The insert valve VS type is recommended for working flow up to 35 lpm (9,2 USgpm) and working pressure up to 500 bar. (7250 PSI) The valve is composed by a body, a ball and an elastic ring, without the presence a pressure setting or repositioning spring. The body valve, thank to its very small dimension and the male thread BSPP 3/8” allows to fit the one-way restrictor VS dirtectly into the working ports, below the coupling (after verification of the deep of thread into the port). Any other additional component for housing isn’t this way needed. The simplicity and the small dimension of the valves VS series represent therefore the right characteristics for the design of systems where is fundamental the compactness and the cost containment.