Spray gun kit, associated method of use and gun

A kit for a spray gun comprising:

• a sleeve extending along a main extension axis, delimiting an inner volume, the inner volume being provided to contain a pressurized fluid, the sleeve being configured to be connected to a main body of the spray gun, the sleeve having a radial periphery, the sleeve being provided with at least one orifice, the at least one orifice emerging on the radial periphery and fluidly connecting the inner volume and the radial periphery, the radial periphery delimiting a fluid outlet of the sleeve;
• a connector having an intake end and a connecting end, the intake end being connected to the fluid outlet of said sleeve, the connecting end being suitable for being connected to a cup so as to fluidly connect the cup to the inner volume of said sleeve;
• and
• a ring surrounding said sleeve,
• wherein said sleeve and/or said ring have a recess indented on the radial periphery, said at least one orifice emerging in the recess,
• wherein said ring and/or said sleeve are provided with O-rings located in front of and in back of the recess, where front and back are relative to the direction that the gun sprays, and
• wherein the ring covers the recess on the radial periphery outside the intake end of said connector,
• wherein the kit selectively withdraws the pressurized fluid from the inner volume, in order to pressurize a fluid product contained in the cup.