Casio PT-12 keuboard works great! All buttons, keys, and controls function as they should. Overall good conditon aside from some scratches/scuffs on the bottom. No battery cover. Uses 4 AA batteries. I have tested it and cleaned it. I removed sticker residue over the plastic engraved label on the bottom, where it has engraved in it "Casio PT-10" so I'm guessing those sticker remains had the updated "PT-12" written on it. Keyboard works excellently, thanks for looking!