The Nero Bluetooth 4.0 Audio AUX-Adapter can be used anywhere:

In the car: Plug the Nero Bluetooth 4.0 Audio AUX-Adapter into a USB power source (e.g. charger on the cigarette lighter) of your car and connect it to the AUX port of your car.

The advantage: No more annoying charging! The Nero Bluetooth 4.0 Audio AUX-Adapter is always ready for use and starts automatically when the car is started.
Smartphone: Connect your phone to the Nero Bluetooth 4.0 Audio AUX-Adapter via Bluetooth (find Nero AUX audio) and start playing your favorite music or podcast

$28USD