The Whirlwind THS 1M Push-to-Mute Talkback/Headphone Sports Announcer Box is configured with a single momentary switch to control the microphone output. The THS 1M has a Push to Mute switch. The microphone output of the THS 1M box is a passive, straight through connection from the microphone input. This ensures that the microphone will still be live on-air, even if power to the THS 1M is lost. Phantom power can also be supplied to a condenser microphone through the mic output from the broadcast audio mixer. A jack is provided for connection of an optional momentary footswitch to control the mic operation. It is ergonomically designed to put the control buttons within easy reach of the announcer even while shuffling through stat sheets. The headphone amplifiers are designed to deliver powerful, undistorted audio that can be heard over an arena full of screaming fans. The Headphone inputs consist of balanced left and right inputs on separate female XLR connectors. A single front panel volume control adjusts the level of both the left and right earpieces. Another balanced mono Aux input is provided which feeds left and right ears equally. The Aux input has its own volume control. Headphones with impedances ranging from 30 to 600 Ohms can be driven to full volume. The Power is supplied by a 12 VAC power adapter included with the unit.