... extend external audio sources, like PC, MD, PSP, GPS Navigation and Mobile Phone Easy to install and use,without changing the car origional ... extend cable, 3.5 line audio cable,usb reader,user manual: Installation Guide:The first and most important step in using ... &Fast Rewind etc.Press “Repeat” button to switch between MP3 and Aux in.Install illustration: car audio usb interface CE,FCC,RoHS approved