Description

Fearns International Unit Conversions Calculator. Navy blue plastic case.

A 5″ (127 mm) double-sided circular calculator with clear revolving disks on both sides allowing conversions to be made. On the front scale are lengths, areas, volumes, mass, force and velocity. On the back scale are energy (or work), density, pressure, power, volume flow and heat flow.

Image 3 shows an example of a conversion where miles (on the front scale) is set to 100 and to the left 800 furlongs and 162 km can be read.