6 + 9 Pfg on art paper, imperforated in the colour error blue INSTEAD OF violet, how overexerted without gumming, proof with a presumable impression of ONLY 30 pieces !!! The condition is perfect certificate Zirath BPP (2011): ". It is here a proof. The impression is presumably only 30 pieces. On the reverse signature "Bartels" ".Michel 4.500. item piece!