A car has nothing to do with Bluetooth except to power it.
A bluetooth headset is the receiver. It hangs on one ear.
The transmitter plugs into the earphone jack of your cell phone or maybe an ipod will drive it.
I was looking for something that would allow me to play music from my phone to the car stereo for when I start driving, that is why a FM Radio Transmitter sounded appealing, because radio FM is almost universal in most cars.