A two component spray gun with low/high flow rates allows the operator to spray in confined areas at lower flow without having to change the mix module. The lower flow reduces undesirable “spray back” and will also help reduce material waste. Pneumatic piston 12 travel, which determines on/off fluid flow, can be selected on the fly to either close the fluid ports 14 which stops fluid flow, partially open the fluid ports 14 which limits fluid flow, or to fully open the fluid ports 14 to allow for maximum flow. Pneumatic piston 12 travel can be limited by means of a simple multi-position mechanical stop plunger 16. The stop bar 22 can be connected to a knob 18 or other operator input and turned or adjusted to the desired position