The Aerpro APUSBD2 USB Extension Adaptor provides a professional and discreet solution for accessing the rear USB input on an aftermarket headunit in your vehicle. With an easy to install plug and play design, it simply replaces the accessory socket in the vehicle and connects to the rear USB input on compatible aftermarket headunits. Once installed, the USB port will enable compatible devices to charge as well as sync* with the aftermarket headunit.