This Antenna Adaptor fits many European vehicles, including the new 2008-up SMART for two/451 and allows AM/FM radio when installing an after market car stereo. The adapter allows you to replace the factory stereo with any after market radio and receive AM/FM signals as the factory antenna adapter is not the standard after market size. Installation is straight forward and simple. If you are planning on changing the radio in your VW/Mercedes/BMW/SMART car, this Antenna Adaptor is typically required.