Jupiter Jack is an easy to use device that turns your car radio into a hands fee speaker phone. It is easy to use. Simply plug Jupiter Jack into your cell phones headset jack and tune your car radio to 99.3 FM and start talking hands free. Its that simple. Jupiter Jack features a built in microphone that transmits your voice clearly while you hear your callers voice clearly through your cars speakers. Using a cell phone without a hands free device may not be sage and is illegal in many states. Now you will enjoy clear robust sound that only your car speaker can provide allowing you to conveniently talk and drive at the same time. Jupiter Jack works with any cell phone with an headphone jack. Some phones may require an adapter, the most common of which are included in the package.