This is a model of a section of a relatively late Comptometer, a full-keyboard non-listing adding machine built in Chicago.
This model has one column of white plastic keys and two partial columns. Odd numbered digit keys are concave, even numbered ones, flat. It has a steel mechanism, aluminum numeral wheels, a bell, and a metal handle to the right of the keys. Next to the keyboard at the back right is a red key. The model has no case. A label received with the collection dates the model M Comptometer to 1939.
The machine was part of the collection of Felt & Tarrant Manufacturing Company, makers of the Comptometer. It was donated to the Smithsonian by the successor firm of Victor Comptometer Corporation.