The Pro Co Panic Button mic A/B Box is designed to give live entertainers on stage a way to redirect their microphone output from A (front-of-house normal operation) to B (sound to an engineer or roadie). It provides you with a way to discretely ask for a mix change or help when a string breaks or a battery dies without doing so over the main system. Channel B can be used simply as a muting switch for the main system. Both A and B outputs will supply phantom power so no pop occurs when channels are switched. If the Panic Button's battery dies, the circuit automatically returns to channel A.