Metra Electronics 40-VW10 Factory Antenna to Aftermarket Radio Adapter for Select 1988-Up Audi/BMW/Mercedes/SMART Vehicles Factory Antenna to Aftermarket Radio Adapter For select 1988-2005 Audi/BMW/Mercedes vehicles Factory antenna with flat plug to aftermarket radio A capacitor is included to match impedance Some newer European radios also have capacitors that do not allow this adapter to work properly (try using 40-VW12)