Check the listing for details. Vintage Adding Machine COMPTOMETER Felt & Tarrant - Model F - Chicago TBE. Listed at 256.36 USD. Comptometer (mechanical calculator with keys) from the famous American brand Felt & Tarrant Mfg. Co.Chicago. It is a Model F (produced between approximately 1915 and 1920), recognizable by its diamond-shaped nameplate and its beautiful metal dress with ornamental patterns on the sides. This model is a centerpiece of early 20th century office engineering. The keys press in and return correctly, the calculation mechanism activates and the side lever allows the counters to be reset to zero. • Aesthetics: Very good general state of conservation. It has a superb original patina. Some normal signs of use for its age (over 100 years) which give it all its vintage charm. • Keyboard: Complete, with its original two-tone keys (black and beige/ivory). • Inscriptions: Clearly legible identification p.