15 Heller imperial yacht unperforated, impeccable mint never hinged outstanding quality from upper right corner (margin defects and crease in the margin of sheet, stamp impeccable and without any signatures, photo expertize Steuer VOeB: \"mint never hinged, qualitatively perfect, unsigned\", Michel 2.000.- - very rare! Issued only 100 pieces (a sheet), the 1997 public war auctioned, in many collections missing stamp!