Connects 2 have designed a wiring harness to convert your cars internal manufacturing wiring loom to the standard European iso harness that is used on all third party headunits. This makes installing a headunit as simple as plug and play. Your cars cable plugs in to the adaptor and then that plugs in to your new headunit. This then provides power to your headunit and output to all your speakers. Please check the year and model of your car.