 Ruben teamed with Philip Mallory to create what would become Duracell International.Ruben developed the mercury button cell in 1942 to replace the zinc-carbon batteries at a request from the Army Signal Corps.With over 100 inventions credited to him personally, one of the most important was the dry electrolytic aluminum capacitor, the solid-state magnesium/cupric sulfide rectifier (a device that converted regular household electric current for use in radios), and the vacuum tube relay, the quick heater vacuum tube, and the concept of a balanced-cell mercury battery.