Expansion Pak

The Expansion Pak is a peripheral for the Nintendo 64 released in 1998. The Expansion Pak is a 4 MiB (RAM) cartridge that inserts into the top of the Nintendo 64 (bringing the console to a combined 8 MiB of contiguous main memory). It also can increase the screen resolution of certain games from 320 x 240 pixels to 640 x 480 pixels. It was used mostly for video games whose save files could not fit on an average Nintendo 64 Cartridge.

The only video games that require its use are The Legend of Zelda: Majora's Mask and Donkey Kong 64. Also, without the Expansion Pak, a significant amount of content in Perfect Dark is inaccessible.