6 Pes. 25 C. On 5 Mark "Reichspost", block of four with following types (from left above to at the bottom on the right) : 19 I / IV plus 19 I / III plus 19 I / I and 19 I (IV, overprint type I, mint never hinged, very fine, very scarce unit, expertized Georg Buehler and photo expertize Ronald F. Steuer BPP "very scarce unit. In perfect mint never hinged condition. ", Michel 5.550.- plus plus