Notes: "The NOVUS 4525 calculator, made by National Semiconductor, is a full scientific programmable calculator that uses RPN rather than algebraic logic. This one works, and charges up with the supplied AC adapter. It appears to have permanently installed nicad batteries, as there is no easily accessible battery compartment. You would have to remove the 4 screws holding the back on to replace the batteries, assuming they are replaceable. This one came complete with the case, AC adapter/charger, and the instruction manual. "