This part goes into the top of the gun, and the cup threads into it. Part number 93505421 or 4-1 in ls400 repair diagrams
Iwata LS400 WS400 Fluid Adjustment Knob 93505831 Supernova
Iwata LS400 WS400 Fluid Adjusting Guide 93505492
Iwata LS400 WS400 Fluid Screw Assembly 93505822
Iwata LS400 WS400 Air Adjustment Assembly 93505842
Iwata LS400 WS400 Fan Adjustment Knob 93505471 Supernova
Iwata LS400 WS400 Pattern Adjustment Valve 93505432
