In December 1942 Byron Phelps and C. A. Bergfors at IBM's Endicott Engineering Laboratory at Endicott, New York completed a prototype of the the Vacuum Tube Multiplier. This was first complete machine to perform arithmetic electronically. By substituting 300 vacuum tubes in flip-flop circuits for electro-mechanical relays it could process information thousands of times faster than electro-mechanical calculators.
In 1946 IBM commercialized the Vacumm Tube Multiplier, calling it the IBM 603 electronic multiplier. This special purpose device was the first electronic calculator ever placed into production, and altogether 100 603s were manufactured. The 603 consisted of two boxes: the Type 603 calculating unit and Type 520 punch-read unit. This machine provided multiplication speeds several magnitudes higher than earlier electromechanical devices.