The AC/DC EL750 is a used Electronic Load.
Product Specs:
The AC/DC EL750 Electronic Load is a precision programmable electronic load test instrument capable of dissipating up to 750 watts of DC power.
Other Info:
The AC/DC EL750 is a small, compact, portable unit designed for use in laboratories, quality control and receiving inspection departments. The AC/DC EL750 operates in either a constant current or constant resistance mode, selected manually with front panel push buttons. The front panel contains all the controls for manual operation and indication.