Faber Castell 57/74 system Schirdewan Textile slide rule 1965 Germany

This is an unusual Faber Castell slide rule special made for the textile industry. It carries the model no. 57/74 based on the system by mr. Schirdewan. The slider has 2 sides featuring Z1 and Z2 scales) and it has an extra wide cursor. It comes in a plastic generic Faber Castell signed case. The cursor is in great shape but the rule has some 2 heat marks on top (does not affect the function) and there are signs of use and age. It measures ca. 30 cm or ca. 12 inches. Check the attached video on how to work your vintage man tool : slide rule operation instructions!