Remember back when Nintendo lifted the lid on the Game Boy Advance all those years ago? It showed the system in two colourways which were never officially released, both of which had silver bodies.

These 'prototype' models are something of a collector's item, and it turns out one of them has been sold via a Yahoo Auctions Japan in a job lot of handhelds. You can see the actual system itself in the video above, and it has some notable differences when compared to the retail version of the console.

For starters, the boot-up sequence has different audio, while the L and R triggers lack the 'lip' that is found on the final model. Furthermore, there are slight differences in the PCB layout and the screen displays problems when running titles that were released well into the GBA's lifespan.

If you've come across a similar GBA console, then you could be sitting on a pretty rare collectable.