RATIBOR19.1.1921 ZKr (274.3) on cover with mixed franking 10 Pfg / 20 Pfg blue block of four center piece with all overprint types I-IV (field 45-46 / 55-56) provissional issue 1920, 50 Pfg grey postage stamps issue smelting works and peace pigeon to Uerdingen, arrival postmark ZKr UERDINGEN 21.1.1921 (274.3) at back, very neat and clear postmarks repulses, good condition