The Expansion Pak allows the random access memory (RAM) of the Nintendo 64 console to increase from 4 megabytes (MB) to 8 MB of contiguous main memory. With the help of an included key, the Expansion Pak fits into the slot that is below a removable panel on the top of the N64 console. Game developers can take advantage of the increased memory in several ways, including making games that are more visually appealing. Some games will allow players to choose a "high-resolution" option, increasing the screen resolution from 320 by 240 pixels to as much as 640 by 480 pixels--creating crisp, high-definition graphics. The Expansion Pak utilizes Nintendo 64's capability for 32-bit, 16.7-million-color display with 256 levels of transparency (alpha)--bringing your games to a new level of realism. Instead of reusing texture data, games can buffer a larger number of textures for a more distinct look.Retro Bit Nintendo 64 EPansion Park

• Cartridge is inserted into Nintendo 64 console; doubles original 4MB of memory, for a total of 8MB
• Allows 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 pixels
• Required for games like Donkey Kong 64