This is called an Addometer Calculator in black case with original directions on use in purple velvet lining.  The machine was made by the Reliable Typewriter & Adding Machine Company.  Stylus is original and plugs into side of machine by reset lever.   The machine operates perfectly with all 10s carries over and reset bar clears to zero.  These treasures were made from the 1900s to early 1950s.  We believe this model dates to 1920s.  It is in very good display and operational condition.  Box Size is 12” x 3.5” x 1”.  The Addometer is a wheel and stylus type adder.  It has a ruler on topside to measure 0 to 11”.  This will highlight any collection of old 90+-year-old calculators.