The Harder & Steenbeck fPc (Fine Pressure Control) Valve replaces the air valve & allows precise control of air pressure directly from your airbrush. Airflow is adjustable between 20 to 100%. For Evolution, ultra, Infinity and Focus.
The K250 External Mac Valve by Iwata is a great addition to any airbrush. This Mac valve allows you to adjust your preassure on the fly without having to adjust it at your air source so you can turn it down for a stippling effect or turn it up all the way up for broad coverage. Works with most airbrushes with the iwata style 1/8" threads.