2 Pesa Imperial Yacht, no watermark, horizontal pair, imperforate proof from trial sheet, Friedemann No. P18, still in light medium brown shade, unused with hinge remnants on bottom margin, wide margins all round and left sheet margin, expertised Köhler, photo certificate Dr. Karl Pauligk BPP (2001) "very well preserved.... multiples of this proof are very rare", Mi. 6.000.-