The MBO 121-MR is an arithmetic calculator with 12 digits precision and algebraic logic. It has 8 functions, 26 keys, and a VFD (vacuum fluorescent) display. The power source is 4xAA. Note: Casio 121-MR
Facts at a glance:
If you have a MBO 121-MR that is no longer working, you can first try replacing the 4xAA batteries. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent.
We suggest the following current models as possible replacements: