Nestler 0432 Schäfer reinforced Concrete slide rule Germany 1950

This early slide rule comes in a blue unsigned cardboard container, with has sticker from a Librairie Papeterie (book and paper star) called St. Pierre SA from Lausanne Switzerland. This slide rule is for calculation of reinforced concrete per the system of Dr. Schaefer from Germany and produced by Nestler. It is interesting since it has scales on the front and back of the slider 1400 Kg/cm2 and 1200. But it also has scales on both small sides. Curser and rule are complete with minimal signs of use and age. On the back of the slide rule are instructions in German. It measures 29,5 cm or 11 1/2 inches. Do check the video below on how to work your vintage man tool : slide rule operation instructions!