The Visual Memory Unit is for Sega's Dreamcast game console and connected to the systems controller to interface with games. It was a truly innovative, but underutilized accessory by game developers who used it to simply save data, which it did wonderfully.  The V.M.U was more than a glorified memory card; it was something that could easily enhance any game, if only a little extra time was invested into the overall product. Unfortunately only a modest handful Dreamcast titles took advantage the V.M.U, like Jet Grind Radio, Power Stone, Shenmue and Street Fighter Alpha 3 among others that added extra features or mini games. The Visual Memory Unit design resembles a miniaturized version of Nintendo's original Gameboy. The LCD screen is placed above the D-pad and other buttons, which are situated close together., but the whole unit fits nicely in the palm of your hand.  Even though the 200 blocks of memory on the V.M.U is enough to store numerous average sized save files, it leaves very little room when saving games like Sega's classic 2K sports series that require more space. Perhaps because of the modest storage size, but files aren't prone to being corrupted, even after nearly a decade.  Overall, the Visual Memory Unit is a necessity for any Dreamcast owner, but I'd highly recommend purchasing a spare as a backup (units can even interlock to exchange files). Beware though, the V.M.U drains batteries at an alarming rate, but time sure does fly when your having fun!