Headset for wireless pac Lightweight headworn hypercardioid microphone with smooth, articulate sound. For situations where gain-before-feedback is less critical. The microphone is unterminated for use with a wireless microphone transmitter of your choice. The Crown CM-312 is a professional, lightweight headworn electret condenser microphone with a hypercardioid polar pattern. The CM-312 utilizes Crown's unique Differoid technology, effectively isolating desired vocals from unwanted background noise. Differoid Noise Canceling Technology Differoid noise canceling rejects ambient signal at a distance, improving signal-to-noise ratio. Filters Electronically controlled bass roll-off Power 48-volt Phantom Powered or 9-volt Battery Lightweight Headset Design Behind-the-ear design is completely lightweight, adjustable, and will conform to any size head.