Mechanical calculator

Addiator
Mechanical calculator
Napier's Bones
https://www.facele.eu/index.php/mechanical-calculators/napier-s-bones
Otis King
Mechanical calculator, Otis king 1966. With a log-scale decade length of 66 inches, the Otis King calculator should be about a full digit more accurate than a 6-inch pocket slide rule. But due to inaccuracies in tic-mark placement, some portions of its scales will read off by more than they should.
Addometer
The Addometer is a mechanical adder which in terms of use and external appearance resembles Blaise Pascal 's pascaline . http://www.facele.eu/mechanical-calculators/addometer
Otis Kings mechanical calculator