Large mechanical calculator made by Olivetti in 1960. This is an early model (round shaped keys) Summa Prima 20. In great working and cosmetic condition, very clean, was obviously not used much. Comes with an installed black/red ink ribbon (though not sure how much longer it will last), a partial tape roll, as well as a box containing 3 new rolls. This particular model is for decimal calculations. A classic and wonderful machine.