The Connects2 CT27AA56 allows replacement of the factory Premium or Navigation Radio with an aftermarket radio and retains use of the factory diversity antenna system. * Connect the 12V antenna turn-on lead wire from the aftermarket radio (usually blue) to the CT27AA56 single blue wire (color may vary) to turn ON/OFF the amplified antenna whenever the radio is turned ON/OFF. * Connect the dual FAKRA terminals to the matching terminals on the car side and the standard DIN Plug into the aftermarket radio. * Fits 2006-Up A3, A4, A6, A8 , TT, most 2006-Up Git, Jetta, Passat, Eos, Touareg, Tiguan etc. * 1-year limited parts and labor warranty. Replacing the OEM factory with an aftermarket radio in VW Diversity Antenna Systems pose two problems: 1. The aftermarket radio has a standard DIN antenna terminal which does not match the dual FAKRA terminals in the vehicle. 2. The diversity antenna system means they are two antenna terminals. The Connects2 CT27AA56 resolves this connecting issue in VW "Premium Sound System"/"Radio-Navigation system" with Diversity Antenna integrated into the rear window. Diversity functions serves to improve and optimize radio reception quality in the vehicle. In these vehicles the strength and quality of the signals received by the two diversity system antennas is continuously monitored and evaluated by the radio unit.