Volkswagen uses a non-standard jack on its antenna cable that won't plug into your new replacement radio. This simple in-line adapter has a standard male Motorola antenna plug on one end, and a female Volkswagen/Audi jack on the other. Just connect your Volkswagen antenna cable to the adapter, then plug it into your new radio, and you're good to go. Warranty: 60 days.
If you're adding an FM modulator to your factory stereo, a second adapter is also required. One adapter will connect to your factory stereo, while the second connects to your factory antenna cable. Your FM modulator installs inline between the two adapters.