3 Ngr. King Johann I, two folded letters each with a single franking, but the essential feature is the Prussian frame railway post stamp POST SP. BUER. IV. GOERLITZ-KOHLFURT, which exists once in black and once in red. According to the Grobe handbook, the red one is already valued at approximately 600 euros, while the black one is reportedly even rarer and difficult to estimate. Both letters are in excellent condition.