75 Pfg blackish blue green / black with proof overprint in brown red colour on cover to Stettin, ZKr MARIENWERDER 10.4.20.1-2 N * (WESTPR. ) a, according to Friedrich Karl Vossen comes the proof overprint from of the printing plant resentment and was with the plate 3 executed, indeed it is is unverifiable, that the letter actual postal was transported, therefore only as used offered, signed Dr. Oertel, photo expertize F. K. Vossen