This is a new Volkswagen Car-Kit Interface Harness - VW P/N 3B0051434, similar to and the functional equivalent of 6X0 051 434 . This harness is used for integrating a handsfree phone kit (bluetooth or wired) into your VW. This will connect to Premium 6 or 7 level radio, with a Telephone Mute connection and Telephone Audio inputs - many times the connections will be labeled on the top of the radio. Roughly, MY2002 and later double-din VW radios had support for this. This handsfree wiring harness can be directly connected to Motorola IHF and T605/T603 series carkits equipped with the 8pin interface connector. On activation of the Mute line, the audio will switchover to the handsfree kit. You can also use this harness to integrate audio into your car stereo from other mono sources by triggering the mute enable line (navigation units, radar detectors, CB radios, etc.). Available on the connection to the carkit is: •VBATT - constant +12V power supply •Ground - chassis ground •Ignition - switched +12V signal •Mute - active-low trigger Mute connection •Audio (+) - differential mono audio signal from the carkit or device •Audio (-) - differential mono audio signal from the carkit or device I have a mobile electronics installation business, and am selling off some excess inventory. Please feel free to send a message if you have further questions about any of my items. Thanks for looking!