How well would this work in a car?

I would like to use this in my parents cars so that I can broadcast my music over bluetooth to the car's stereo without using radio frequency. I want to know how well this would work when plugged into the car stereo via a cassette adapter. This would allow me to control the audio and keep my iPod Touch in my holster without having to unplug an audio cord from it when I get out of the car as well as control the audio from the backseat when one of my parents is driving.

Also, does this have to be plugged in to work or does it have a battery?

I just want to know before I go spend $50 on it and then possibly find out that it doesn't work as well as I had hoped.

Belkin Bluetooth Music Receiver

Belkin Bluetooth Music Receiver

Product No Longer Available

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