Cartridge is inserted into Nintendo 64 console; doubles original 4MB of memory, for a total of 8MBAllows games to have larger worlds, longer animation sequences, and much more complex gameplay.Increases screen resolution from 320 X 240 pixels up to 640 X 480 pixelsRequired for games like Donkey Kong 64Pre-owned Guarantee. This pre-owned product has been carefully tested, and is guaranteed to work. If you are not completely satisfied, simply return the product within 7 days for your money back. Product may not include original box and instruction manual. Item pictured may not be exact item received.