FM transmitters with hands free
prices on 20 models— the speakerphone implies the presence of Bluetooth (see the relevant paragraph) and allows you to conduct conversations by broadcasting the voice of the interlocutor through the car's speaker system. This is the best option for talking on the phone while driving — the phone does not need to be held in your hand, and the audibility is better than from the device's own speaker.
At the same time, it is worth noting that the presence of Bluetooth in the FM transmitter does not mean the presence of this function.