Aristo 40140 BG Concrete slide rule case 1950 Germany

This special slide rule comes in the original leather sleeve (unsigned) and is made by Aristo from Germany. This model is the earlier 40140 BG (probably 1950’s) a special slide rule made for the Company Baustahlgewebe from Düsseldorf Germany. This slide rule is specifically made for calculating concrete steel mats for use in construction. It has scales on the front and back of the slider (one red, one black). Curser with 10 hairlines and rule are complete there are signs of normal use on the slide rule and cursor. The sleeve is in complete and in good condition as well. It measures 32 cm or 12 1/2 inches. Do check the attached video on how to work your vintage man tool : slide rule operation instructions!