Notes: "The Addiator Arithma was advertised as the “World’s Smallest Precision Adding Machine”, which may have been true at some period in time, depending on how you measure “smallest” and how you define “precision.” This is the version of the Arithma with a brass outer shell vs. the more common aluminum models. I believe the inner workings are aluminum on both models. You can tell that it’s brass and not brass-plated aluminum by the weight: approximately 36g for the aluminum version, approximately 53g for the brass one. "
