Just hit the footswitch and anything plugged into the input is made 100% silent. Has a dual color LED that shines green when signal is hot and red when the mute is on.
NOTE that this is NOT a momentary switch. When clicked, the signal stays in the position chosen.
This pedal is passive but requires standard 9V DC Negative for the LED to function and it measures 3.6"x1.5"x1"