This CANBus steering wheel control interface will allow you to retain the use of the steering wheel audio controls.Gives volume, seek, source, and telephone commands to an after market radio.It has universal wiring so it can be used a variety of Audi cars with different audio systems. Integrates with audio adapters that may already be present or use with the InCarTec ISO amplifier adapter or quadlock amplifier adapter for the best levels of audio quality.The CANBus interface will generate an ignition power supply to the new radio, it will also give out an illumination signal, speed pulse signal, reverse gear output and handbrake output.This interface needs to be used with a 49-Series Patch Lead to suit the make of head unit that is being fitted.Helpful Information & Links: User instructions