At this point we installed the provided thumb drive into the USB-style input. As we have already discussed, there are inputs for every sort of source we can imagine. The thumb drive comes from Custom Autosound loaded with information about the Secretaudio system, and the company's other available systems as well, to view on your computer. There are also sample tracks of music for you to enjoy and use to test out your new stereo right away. Once you've heard what's on the thumb drive you can delete the contents and use the drive to store several CD's worth of music. Of course, once you connect an iPod then you'll have almost infinite capacity. You can also purchase USB extension cables at any computer supply/electronics store to place your source connections in an easier to reach location, such as a glovebox or console so you don't have to plug your MP3 player in under a seat or in the trunk.