It is plugged into the controller and allowed the player to save game progress and configuration. The original models from Nintendo offered 256 kilobits (32KB) battery backed SRAM, split into 123 pages with a limitation of 16 save files, but third party models had much more, often in the form of 4 selectable memory bank of 256kbits. The number of pages that a game occupied varied (sometimes, it used the entire card). It is powered by a common CR2032 battery.A Controller Pak was initially useful or even necessary for the earlier N64 games. Over time, the Controller Pak lost ground to the convenience of a battery backed SRAM (or EEPROM) found in some cartridges. Because the Nintendo 64 used a game cartridge format that allows saving data on the cartridges themselves, few First-party developer and Second-party developer games used the Controller Pak. The vast majority were from third-party developers, likely because of cost expenses: including self-contained data on the cartridge would have increased production and retail costs. Some games used it to save optional data that was too large for the cartridge, such as Mario Kart 64, which used 121 pages for storing ghost data. Another game is Tony Hawk's Pro Skater, which uses 11 pages. Quest 64 and Mystical Ninja Starring Goemon used the Controller Pak exclusively for saved data. The Japan-only game Animal Forest used the Controller Pak to travel to other towns.