The Whirlwind Micmute Push to Mute Latching Push On/Off Foot Pedal Mic Switch meaning that the switch must be pushed and released to turn the signal on or off through the box. Each time the switch is pressed and released the signal is changed from one condition to the other. The PP have an indicator LED feature that is operational when the connected microphone preamp input is providing phantom power. The blue LED illuminates to indicate that the mic is live and signal is passing through the Micmute box. The LED is not functional when phantom power is not present.