The FX2 Mixer is a DUAL mono input line mixer with a simple pair of level controls and a pair of panners. The FX2 has a unique MUTE circuit that when pressed, the LED turns RED, but when the module is ON, the LED serves as a level presence indicator, illuminating green to show signal presence. There is a PB board selector jumper to choose between PRE (factory standard) and POST for the level led. This is very useful in live recording when you need to know quickly if a channel has signal or which has the loudest signal on it. It is also perfect for identifying which channel has the Kick and which has the Snare, etc.