1923, 50 C. Airmail issue, variety \"unperforated\", from right margin of sheet, mint never hinged, faultless condition, issued only 50 examples, photo expertize Emil Rellstab BPP and photo expertize Jean Claude Marchand SBPV (2023) \"in perfect condition. \" Michel 6.000.- (Zumstein no. 9 to 1.09)