It depends on the console you have. HuCards don't have any internal back-up RAM. If you have a CD-based system, then your games are saved in the back-up RAM integrated to the system. If you have a PC Engine, CoreGrafx, SuperGrafx, ShuttleGrafx, etc, you'll need an external back-up system (Ten no Koe 2, Back-Up Booster 1 or 2, Back-Up Unit).