This is a Nicestuff 68300 (also known as the PR300 or NSD-68300 or 68300-PAC EasyMute) handsfree integration harness for use with vehicles with ISO radio connectors and premium audio systems with an external amplifier (ex: BOSE, JBL, Harmon-Kardon, Infinity, etc.). This kit features a soft-mute switching relay that sits on the line-level signal between the radio and the amplifier to provide a clean swithcing of the radio audio to the handsfree audio. 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!