Used Bose A20 headset. This model comes with a single U174 connector, low impedance microphone and no Bluetooth. The headset has recently had its ear cups and foam replaced, and the fur head protector has been cleaned. The noise cancelling, audio input and microphone output have been tested and work well. The unit will come with the black headset carrier. One of the small rubber connectors on the battery door has detached (picture 7). Please feel free to message with any questions.