Infinity Quick Fix Rear BodyKnob for limiting the needle travel range and thus the painted line width. For H&S infinity airbrushes. manufacturer's catalogue number 126667 Compatible with all variants of H&S Infinity airbrush By pressing trigger down we open air flow and by pulling the trigger backwards we start the paint flow. The further we pull the trigger the more paint will be dosed thus creating wider paint line. This endpiece features needle travel limiter with a Quick Fix