Aristo 90172 ARG pocket slide rule pipes Nagel full set 1957 Germany

This pocket slide rule is made by Aristo from Germany according to the design of A.Nagel from 1957. It has the number 90172 and has been made especially for ARG Company from Germany. It calculates pressure of water and steel in pipes under different circumstances. This full set contains the slide rule in a it’s ARG marked leather sleeve (also signed Valmet) and with a dedicated (also ARG marked) instruction booklet with black and red text and pictures. The small cursor is present and the slider has 2 sides. The case and slide rule are all complete and in very good condition with only small signs of use and age. The case measures ca. 25 cm or 10 inches. Check the attached video on how to work your vintage man tool: slide rule operation instructions!