The Neo-Key is an early USB modchip for the PS2. You needed a GS or AR2 cheat disc to play imported/backup discs via swap method, long before there were no-swap chips available. These boards were designed in EAGLE and each version uses a different form-factor; V1 is made to be compact and fit just like an Original Neo-Key, and V2 is shaped like a flash drive where it will stick out.