Nestler 0149 Maarschalk Concrete pocket slide rule Germany 1970

This is the pocket version concrete slide rule by Nestler from Germany. It does not have a number on it but it seems to be model 0149. This slide rule is for calculation of reinforced concrete (Stahlbeton) per the system of Maarschalk (n= selectable). It has a special scale on top and formulas on the bottom. The slider also has some basic scales on the back side. It has the original pouch with Nestler name. It is all complete and in great condition. It measures ca. 15 cm or 6 inches. Do check the video below on how to work your vintage man tool : slide rule operation instructions!