This is a Peripheral (now PAC Audio) PPH8590 handsfree integration harness for use with select BMW vehicles. Use this harness with a Peripheral MSS switching relay to integrate a bluetooth or phone handsfree system into your vehicle. This harness (with an MSS relay) is similar in function and applications to the Nicestuff 68035 harness. I also have MSS relay switches for sale in my booth. Some of the compatible vehicles include; 1985-1991 BMW E30 3-series 1990-1998 BMW E36 3-series Business RDS or Satellite Nav 1999-2001 BMW E46 3-series Business/Professional RDS 1999-2001 BMW E46 3-series with Navigation (also requires EX899 extension cable) 1999-2001 BMW E46 3-series with Harmon Kardon 1988-1996 BMW E34 5-series 1996-2000 BMW E39 5-series Business/Professional RDS 1996-2000 BMW E39 5-series with Navigation (also requires EX899 extension cable) 2001-2003 BMW E39 5-series with Becker Business RDS 2001-2003 BMW E39 5-series with Navigation (also requires EX899 extension cable) 1999-2003 BMW E39 5-series with Harmon Kardon 1977-2001 BMW 7-series 1989-1999 BMW 8-series 2000 BMW X5 without Nav 2000-2001 BMW X5 with Navigation (also requires EX899 extension cable) 1989-1991 BMW Z1 1996-2001 BMW Z3 and some early 2000's Land Rover vehicles 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.). A carkit-specific adapter harness may be required for your installation (I have some of these in my booth), or the connections can be made individually. 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 Speaker (+) - differential mono audio signal from the carkit or device Speaker (-) - 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. I am willing to ship this item internationally, but please contact me first so that accurate shipping charges can be assessed. Thanks for looking!