If your car radio does not have to answer calls and Bluetooth music cell phone direct transmistir, So buy this small receiver is a good idea.
It has a battery that lasts about 12 h and can be recharged in the car radio USB or a USB adapter for cigarette lighter. The box comes with a P2-P2 audio cable, a small USB cable-micro USB for charging and the receiver itself.
To use the receiver you must press the round button and wait for a central blue led stay flashing. From there just search for bluetooth devices on your phone and pair the receiver. Then connect the receiver audio output P2 in the auxiliary input of the car radio. After all done anything that the phone rings will be passed to the loudspeakers of the car radio. Pretty cool!
In the picture below we have the volume controls of the receiver, I always leave at most to control the volume only on car radio.
In the picture below we have the audio output P2 that goes to the auxiliary connector of the car radio and the micro USB charge entry.
Tested with audio stereo AD2P (media player) and worked normally, with good quality including. When you receive a call the phone audio is also transferred to the car radio, and to answer the call you can use the round central button. A great device for the price, It was purchased in DealExtreme site. I leave the link below for those interested: