For your consideration, here is a Casio FX-7400G Plus Power Graphic Calculator, with cover. It takes two AAA batteries. It comes with the backup battery and has been tested some. I did not try all of the functions. The calculator and cover have some wear and engraving on the back. The cover has some paint on it. The battery compartment has some marker marks inside of it. Item pictured is the actual item up for sale and comes from a non-smoking household. (60.62j-.13hc)