BINAC

The BINAC was invented in 1949 by the Eckert-Mauchly Computer Corporation. It was designed for the Northrop Aircraft Company and used as a calculator for math problems.
The BINAC was the first electronic computer to be sold to an outside user rather than built for a university's engineering department. This is the most important commercial aspect of the BINAC. Another important aspect of the BINAC is that it had 2 CPUs.
One interesting fact about BINAC is that it drew inspiration for its user manual from car user manuals.