Most cars don’t come with a cassette player anymore, but for those that do, hooking up an MP3 player can be bit of a pain. Sure, they have those adapters that feed a cable out the end of a fake cassette tape so that you can connect an external audio source, but those can be pretty cumbersome and ugly.
This funky contraption is lot easier to use, because while it is shaped like a regular cassette tape, it actually comes with an SD card slot and functions like its own MP3 player. Simply insert an SD card filled with tunes into the cassette tape, and then insert the tape into your tape player. The car stereo will then proceed to play the files as if they were on the tape itself.