PAC RP4-AD11 Radiopro4 Stereo Replacement Interface with Steering Wheel Controls for Select Audi Vehicles with Canbus Radiopro4 PAC RP4-AD11 Stereo Replacement Interface Navigation ready: Data controlled accessory and navigation outputs Built in pre-programmed steering wheel control (SWC) retention Retains factory amplifier (In Premium Amplified Systems only two input channels can be used from the aftermarket radio, therefore there will be no fading capability of the aftermarket stereo) Provides factory RSE activation