The Audio-Technica phantom-powered U891R Boundary Microphone features a touch-sensitive on/off switch that can be set to three modes: press-on/press-off, press to talk, and press to mute. The phantom-powered microphone is equipped with a unique PivotPoint rotating output connector and an LED status indicator. UniGuard innovations offer unsurpassed immunity from radio frequency interference; interchangeable elements are available in cardioid, hypercardioid, and omnidirectional polar patterns; an 80Hz low-cut UniSteep filter reduces pickup of low-frequency ambient noise. The microphone's heavy die-cast case and silicon foam bottom pads minimize coupling of surface vibration to the microphone. The unit's self-contained electronics eliminate the need for an external power module.