Very cool feldpost document stamper. The last photo is the actual imprint given. "Dienststelle der feldpost Nr 59 645B". It looks like this was used first in 1943 by Staff and Companies 1-4 of Reserve Panzer Grenadier Battalion 215 which was destroyed in 1944. In June of 1944 this feldpost designation was used by Staff and 1st Battalion Panzer Grenadier Regiment II, also destroyed 1944. Clearly this stamper was bad luck. Very neat, very real item.