Nestler 22R/3 system Rietz pocket slide rule Germany 1940

This is the pocket version slide rule by Nestler from Germany. It has the number 22, also 2 times printed on the top part of the original card board box (some small tears) It is the Rietz model, the pocket version of the famous 23R model. This slide rule is for calculation of the more basic needs, used by scientists and administrators alike. There are 7 scales on the front and 3 more on the back of the slider and a centimer and inch scale on the 2 sides. The stock has the model name and Nestler brand on it. I am guesstimating this one is from the 1940’s. It is all complete with the 3 hairline glass cursor and in very good condition (2 smallest chips on the back missing..price adjusted accordingly). It measures ca. 18 cm or 7 1/4 inches. Do check the video below on how to work your vintage man tool : slide rule operation instructions!