1850 / 54, 2 kreuzer deep black, machine paper, type IIIb, ultra-fine printing, used with blue single circle postmark \"HIETZING 21 / 5 4. E. \" (Mueller 990 b), as well additional complete city mail box postmark \"Vienna 21 - V 11-1 M\" on piece, photo expertize Dr. Ulrich Ferchenbauer VOeB: \"a effective and exquisite item! \"