This is  a military electron tube tester made by Hickok and is model number TV-7B/U.  Did not have tubes to test so I have not actually tested any tubes with this unit.  Pilot lamp lights when power is applied.  All switches, knobs and push buttons seem to operate properly as far as locking into position etc.  PLEASE NOTE:  ACORN TUBE SLOT IS BROKEN  !!  Has a Army test data book from Jan. 1962.