Magic Brain: Last Gasp of the Mechanical Calculator

Ingenious Pocket Mechanical Calculator

1950 Curta Calculator

Vintage 1960's Magic Brain Pocket Calculator W/Stylus, Made in

1920s Monroe Mechanical Calculator

Mechanical Square Root and Sine Calculator

Magic Brain: Last Gasp of the Mechanical Calculator

Vintage 1960s MAGIC BRAIN Pocket Mechanical Addiator

Divide by Zero on the Friden STW10 Mechanical Calculator

Magic Brain Calculator - A vintage mechanical addiator type

National Museum of American History

The mechanical calculator for all four arithmetical operations by

My Mechanical Calculator 'Leibniz' on SimplePlanes Simple Planes

Not a pepper mill, a calculator! The Curta all mechanical