15 penny National Assembly with blue hand stamp overprint "C. I. H. S. ", cancelled "Opole * 1 i 19.2.20 5-6 N" on piece, two perforation are slightly yellowish discoloured, expertized MH and photo expertize Gunnar Gruber BPP "genuine and immaculate condition. ", Michel 1.200.- - illustration piece in the handbook (2nd issue, page 67, illustration 4)