A "Head Unit" is the central component of a car's audio system, responsible for controlling various functions such as radio, music playback, and navigation. It typically features a display screen, buttons, and sometimes touchscreen controls, allowing users to interact with their audio sources and settings. Head units can connect to smartphones and other devices via Bluetooth or USB, enabling access to streaming services and hands-free calling. Modern head units often support additional features like Apple CarPlay and Android Auto, which enhance connectivity and usability. They can also integrate with GPS navigation systems, providing real-time directions and traffic updates. Upgrading a head unit can significantly improve a vehicle's audio experience.