Then, an FM transmitter might do the job, as every car stereo has an FM antenna built-in. The Nulaxy Bluetooth Car FM ...

Most FM transmitters are Bluetooth-enabled. All you need to do is plug the transmitter into your car socket, pair your device, and you can start listening to the radio wherever you are.

It also supports storage devices like pen drive and microSD card ... of features in a compact package. Portronics AUTO 10 POR-320, Bluetooth - FM Transmitter in-Car Radio Adapter for Hands ...