Faber Castell Rietz 1/87A addiator slide rule pen case 1960 Germany

Wooden slide rule in the original cardboard green case, by the German company Castell. This is model Rietz 1/87A in good condition, the A stands for the Addiator that is incorporated in the back. This gave the owner the means for simple subtractions and addition with the Addiator as well as more complicated calculations with the slide rule..a true hand held calculator. It comes with the original pen that is seated in the small underside. Everything is in good working condition with some signs of normal use and age. It measures ca. 30 cm or 11 1/2 inches long. Nice all original piece of this well known slide rule. Check the attached video on how to work your vintage man tool : slide rule operation instructions!