Large original tin for Pfeiffer und Dillers coffee stuff. This would have contained a sort of coffee substitute or supplement. These tins do appear from time to time in rations photos. This is a good size to hold a few personal items and to have out in a rations display. It very nice condition with a few dings/scratches, which isn't too unusual for a tin of this size. Its nice enough to show off with just enough damage to not feel to bad taking it out in the field.
I am still not 100% sure what this stuff was for. I have owned full tins and the stuff appeared to have been small compressed material. It seems to either be a straight coffee substitute or an additive meant to make the ersatz coffee more palatable.