An FM modulator allows you to connect an auxiliary device (such as an iPod, smart phone or MP3 player) to a car stereo.
They work by transmitting a radio signal that can be received by the vehicle's FM tuner. The beauty of the technology is that they will work in any vehicle with an FM radio.
The FM modulators from Celsus are available with different options and have a variety of price points. The wireless FM modulator works by broadcasting a weak, low-range signal so your car's radio can pick it up and play it.