Original WW2 slide rule from the German Army. It was used with an 8mm grenade launcher to calculate the angles, elevation errors etc. It has probably been made by Faber Castell and it certainly has the quality. It is stammed GR.W. 34 (which is the grenade launcher model: GRenade Werfer) and also issue by the GWR in May 1943 (on the back it has the stamp 432. It has an unique large and multi colored cursor. While the slide rule itself is only 27cm or 10 3/4 inches long the Cursor is almost 10 cm or 4 inches wide. On the back it has the instructions…all in German of course. It also comes in the original heavy duty GWR stamped case. Slide rule and case are in great condition with only some yellowing on the back of the slide rule. Check the attached video on how to work your vintage man tool : slide rule operation instructions!