50 R on 15 Kopf Worker, dark green, overprint in Type II (swastika 6 mm), stamp from the left edge of the sheet, cancelled with expertized K2 and single-line "Alexanderstadt", flawless condition in typical perforation for the issue, very rare stamp, signed by E Keiler et alia and photo certificate Walter Zirath BPP "The condition is flawless and the irregular perforation is typical.", Michel 7,000.-