Codebreaker
From Wiki - GameHacking.org
A common game enhancer produced by Pelican Accessories.
History
The first CB device was a rebranded Xploder cartridge when released on the Playstation. Later revisions for PSX were likely based off the same software. Other versions have shown up on Dreamcast, GameBoy Color, GameBoy Advance, Playstation 2, and now NDS.
Though the exact details are mostly unknown, CMX had a great deal to do with the CB PS2 development.