Faber Castell 4/60/380 Mannheim 57 cm 23″ slide rule 1936 Germany

This is a extra long slide rule 4/60/380 Mannheim by Faber-Castell. It is the double long version of the 1/60/360 model in order to make more accurate calculations with longer scales. On the back is the number 36 for the year 1936. It comes in the signed black cardboard case that is still complete with only small signs of storage/use, but the top has the wrong number (4/87) so seems to be a later period replacement (price adjusted accordingly). Everything about the rule and cursor is complete, no cracks, chips or dings and in working condition with only small signs of use and age. This rule has a wooden base with 6 screws on the bottom for tightening. It measures 57,5 cm or 23 inches wide. Check the attached video on how to work your vintage man tool : slide rule operation instructions!