2x Norma Mercuria 190 + 100 Technikus circular slide rules case 1970 Germany

Here are 2 metal Norma Grafia slide rules, in close to new condition with their instruction booklets. There is a large one, the Merkuria 190 with a diameter of 19 cm or 7 3/4 inches was produced as a “dealer / Kaufmann” slide rule with simple calucaltions as well as currencies. The small version, the Techniques 100 with a diameter of 10 cm or 4 inches was made for technical calculations (this also came in a larger 190 version). The Norma Company was started in 1959 but these slide rules are probably from the 1970’s considering their pristine condition. The price is for both pieces together. I ams also selling an earlier Rieger Merkuria 190. Check the attached video on how to work your vintage man tool: circular slide rule operation instructions!