The Azden CM-20 Unidirectional Collar Microphone is a heavy-duty adjustable collar microphone, ideal for those not wanting to use a head-worn or clip-on microphone. Comes with a replaceable cable with a wired mini-jack (3.5mm). This omni-directional electret condenser microphone requires a bias voltage of 5-9VDC which all Azden bodypack transmitters provide.