This is a vintage Faber Castell 67/54 Rb Darmstadt Slide Rule w/ Addiator - Made in Germany.  Comes with original zipper case and stylist.  The zipper also has the Faber Castell logo.  The case is green with the Faber Castell mark and made in Germany.  There are some worn spots on the case and residual tape.  The mechanical calculator can do addition and subtraction and has negative number capability indicated by the SALDO NEG notation. Various mathematical formulas such as trigonometric functions and conversion factors are printed on the device.  Original owner.