Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Soviet Union - 1931, Airship over the Arctic Region, perforated (10¾) trial color proof of 50k in dark brownish violet on paper with horizontal watermark Borders and Rosettes, removed from a presentation card with text ''Project'' at the bottom, VF and extremely rare item. Only 48 imperforated proofs in brownish violet color were produced, perforated proofs of this stamp were not offered to the market, V. Zagorsky certificate, Est. $9,000-$12,000, Sc. #C23