This slide rule comes in the original leatherette sleeve (not numbered) as well as with the original manual, all made by Graphoplex from France. This model is the CGGC 2311 also know as the HydroLog, a duplex model with some unusual scales, next to the more standard yet elaborate scales. It was created specially for a company named Lyon Industries Services (LIS) which is still in existence today, that focusses on water related solutions. The rule itself is made of plastic, as well as the cursor. Curser and slide rule are complete and everything is in very good, hardly used condition, with minimal signs of use and age. This slide rule measures ca. 33 cm or 13 inches. The complete French manual shows small signs of use. Do check the attached video on how to work your vintage man tool : slide rule operation instructions!
