The only Powersaves device that I know of is the original Action Replay Powersaves (also known as Powersaves Pro, depending on when and where you bought it). This device is a dongle, and designed specifically to require a retail cartridge in order to function properly. Yet...the game Pokemon Rumble World is listed among those featuring Powersaves and Powersaves codes. Last I checked, Pokemon Rumble World is NOT available in cartridge form. That is, unless I missed it somehow. Or...a new Powersaves dongle has been released specifically to work on eShop games. Somebody clue me in here.