Faber Castell 67/87 R addiator slide rule sleeve 1960 Germany

This is a nice transitional and unusual Faber Castell slide rule that has a double function. It is a combination of slide rule on one side and an addiator on the other side. Made ca. 1960’s with complete plastic slide rule and cursor. The addiator is a predecessor of the basic handheld calculator (as is the abacus) with function that allows for quick addition and subtraction of amounts. The slide rule itself is more the predecessor of the scientific electronic calculator. This pocket version is called the 67/87 R Rietz model. It comes with Faber Castell signed leather sleeve but without pen. It is in very nice condition with signs of normal use and age, addiator functions reasonably well. It measures ca. 15,5 cm or ca. 6 1/4 inches. Check the attached video on how to work your vintage man tool : slide rule operation instructions!