FF33 field phone which appears to be a sort of Frankenstein of wartime parts put together for the Deutsche Reichsbahn. My guess would be that it served with the railroad after the war in East Germany. It is in working order. The case has some repairs (see photos). It clearly has a couple DR eagle stamps in the Bakelite. It was an unusual battery tray which seems to be made to accept the German flat batteries like the ones that go in the flashlight.