The head unit is the main control device for a car audio system. Head units are generally installed in the center of the dashboard or dash panel. Among the most common mobile audio components are in dash car stereo receivers in single DIN or double DIN housings and primarily with an AM-FM tuner. Today, many car stereo receivers have modern features such as video LCD screen, multimedia DVD playback, Bluetooth hands free, XM Sirius satellite capability, iPod hook ups and more.