Game Boy Advance Test Cart
(Aging)

  The Game Boy Advance test cart opens up to an option menu in which you can test several of it's functions individually or run through a burn-in test.  It can be used to test the original GBA and the GBA SP, though I haven't had the opportunity to test it out on a GBA Micro.  This originally came with a yellow back attached (most likely to differientiate it from