An FM transmitter is a device which allows drivers to play portable audio sources through a radio with an FM band – most commonly a car stereo. Since there is no physical connection to the radio, there are no cords required and there is also no need to upgrade the audio system in your car. Essentially, this device works by a converter taking the audio output from a pre-existing source and converting it into analog audio. After this, FM modulation will convert the signal again, allowing drivers to tune their car radio to the specific frequency that matches with the transmitter and listen to music as if being broadcast through a regular FM radio. With Bluetooth connectivity, you can pair it with your smartphone to then play the music from your phone directly to your car’s stereo or answer any incoming calls. Most of these devices come equipped with in-line controllers and display screens, as well as allowing the installation of apps to improve overall audio quality.