6 Pfg numerals green black, officially experimental perforation L11, vertical strip of six with at the bottom attached blank field ++ margin of sheet, the 2 and 3 stamp from above with variety "middle horizontal perforation unusual" (field 43 / 53 of the sheet), edge of blank field affixed spots otherwise faultless mint never hinged condition (between 8. And 9. Sheet row prefolded), photo expertize Dr. Jasch BPP (2017) : "otherwise is the unit - genuine and immaculate -". Very rare in this combination, Michel approximate 1.670.- (free of premium for the scarce unit)