Graphoplex Roplex circular slide rule in red case 1950 France

This is a very good condition fully functional circular slide rule in an unusual square construction….just leave it to the French to come up with a different design!. It is double sided with small adjuster knobs on the top corners. One works the cursor on both sides while the other only moves the scales on the back. It is called the Graphoplex Roplex and comes in the original cardboard case (underside repaired). Everything is working well and in good condition, perfect readability and only some signs of norma use of age. The slide rules measures ca. 15 cm or ca 6 inches wide and high. It comes with a free photo copy of the manual in French. Do check the attached video on how to work your vintage man tool: slide rule operation instructions!