1927 (September 19), the Hague Air Post Conference, 10k and 15k x3, used on registered air mail cover from Moscow to Paris, all appropriate markings and arrival ''21-9-27'' ds, mostly VF, Est. $100-$150 (Image)

1930, Moscow Zeppelin Flight, 40k ultra and 80k carmine, imperforated complete set of two in horizontal pairs, nice margins all around, full OG, LH or previously hinged, VF and very scarce, especially in pairs, expertized by Z. Mikulski and others, C.v. $6,600 as singles, Est. $3,500-$4,000 (Image)

1931 (February 2), mixed franking air mail cover prepared to be sent by Do X Flight through Lisbon and Dakar, however sent from Leningrad to Berlin by plane and forwarded to Colombia by ship, upon arrival uprated by six Colombian adhesives, finally delivered to Cali on March 17 by airplane either from Buenaventura or Barranquilla, mostly VF, Est. $150-$200 (Image)

1934, the Stratosphere Disaster, 5k-20k, complete set of three, each stamp with a part of perfin ''Obrazets'', trimmed perforation by scissors in several places as always on these stamps, full OG, LH, VF and rare set from the Postal Archives, Est. $450-$500 (Image)

1934, Airship ''Lenin'', 30k ultramarine, the ''key'' value of the set, a part of perfin ''Obrazets'', full OG, LH, VF and very scarce, guaranteed genuine, Est. $300-$400 (Image)

1937, Aviation Exhibition, souvenir sheet of four 1r black brown and buff, size 165x90mm, flawless item, full OG, NH, VF, C.v. $450, Est. $150-$200 (Image)

SCADTA FLIGHT COVER: 1931 (May 5), Colombian stationery envelope 4c blue bearing five Soviet adhesives, including 25th Anniversary of Revolution of 1905 and Child Welfare issue of 1929, sent by First Flight ''Leningrad - Berlin'' and forwarded from Berlin (May 6) to Colombia by ship, upon arrival to Buenaventura (May 25) uprated by six definitive stamps and posted to SCADTA Flight to Cali, ''28.V.31'' receiver and all appropriate markings, minor flaws, still F/VF, Est. $150-$200 (Image)

AVIATION PIONEERS AND POLAR RESEARCHERS: 1934-36(c), Heroes of Soviet Union Alexander Belyakov, Mikhail Vodopyanov and Ivan Papanin, Arctic Aviator Yakov Moshkovsky and Arctic Explorer Georgy Ushakov, 7 black-and-white or real photo postcards, very fresh, unused, VF and scarce, printing run of 10,000-20,000 copies, Est. $250-$300 (Image)

1924 (February 2), cover from Povenets (then Olonets Gub.) to Germany, franked by litho definitives 1k-6k and Lenin Mourning stamp of 6k, as well as three War Charity labels were added and cancelled together with postal stamps, mostly VF, Est. $250-$300 (Image)

1924, definitive issue, 4k-30k, complete set of four, litho printing, perforation 14½x15, usual centering, fresh condition, full OG, NH, VF for this issue, C.v. $650, Est. $200-$300 (Image)

1924, definitive issue, peasant 30k violet, litho printing, right margin imperforated single, invalidating perforation across the design, full OG, LH, VF, Est. $150-$200 (Image)

1924-25, definitive issue, 1k-5r, set of 18 values, typo printing on paper without watermark, perforation 14½x15 or 13½, including 1k, 5k, 30k, 40k and 50k, all are genuine without hidden defects, full OG, mainly LH, F/VF, C.v. $2,035, Est. $1,000-$1,200 (Image)

1924-25, definitive issue, worker 14k slate blue, typo printing, perforation 14½x15, excellent quality single with tiny natural paper inclusion at bottom, full OG, NH, VF, C.v. $325, Est. $150-$200 (Image)

1924-25, definitive issue, worker 20k light green, typo printing, imperforated bottom sheet margin single on grayish paper, nice condition, full OG, previously hinged, VF, Soviet Philatelic guarantee hs, Raritan Stamps opinion, Est. $3,500-$4,000 (Image)

1924-25, definitive issue, soldier 3r brown and green, typo printing of type I, imperforated single with four-side margin (enlarged at top and at left), apparently natural thin straight diagonal line on gum, front part is in perfect condition, full OG, LH, VF and rare, Raritan Stamps guarantee, Est. $1,500-$2,000 (Image)

1925, definitive issue, Lenin, 5r brick red and 10r indigo, watermark Borders and Rosettes, two complete sets of two, perforation 13½ and 10½ respectively, full OG, NH or VLH (5r with perf 13½), VF, C.v. $687.50, Est. $250-$300 (Image)

1925, definitive issue, Lenin, 5r brick red and 10r indigo blue, imperforated complete set of two, both are bottom sheet margin singles, full OG, NH, VF, Est. $75-$100 (Image)

1925, definitive issue, Lenin, 5r brick red and 10r indigo, watermark Borders and Rosettes, imperforated complete set of two in left sheet margin horizontal pairs, printer's cross at margin, full OG, NH, VF, Est. $150-$200 (Image)

1925-27, definitive issue, 1k-5r, complete set of 22, including both 10k values, printed on watermarked Borders and Rosettes paper, nice and fresh, full OG, NH, mainly VF, C.v. $507, Est. $250-$300 (Image)

1925, definitive issue, soldier 3r yellow green and dark brown, type II on watermarked Borders and Rosettes paper, perforation 12½ (in certificate perf 12), full OG, NH, VF, A. Farberov certificate, Est. $150-$200 (Image)

1926, definitive issue, 1k-5r, imperforated complete set of 20, printed on watermarked Borders and Rosettes paper, all have enlarged margins, full OG, NH, VF, Est. $150-200 (Image)

1926, definitive issue, 7k-5r, imperforated complete set of eight, printed on white wove paper without watermark, full OG, NH, VF, Standard Cat. #0120-27, Est. $100-$150 (Image)

1926, definitive issue, Lenin, 1r, 2r and 3r, complete set of three, all with sheet margins printed on watermarked Borders and Rosettes paper, perforation 10½, full OG, NH, VF, C.v. $227.50, Est. $100-$150 (Image)

1926, definitive issue, Lenin 2r black violet, perforation 12½, printed on watermarked Borders and Rosettes paper, full OG, VLH, VF, C.v. $2,250, which seems to be an error, Est. $150-$200 (Image)

1927, 10th Anniversary of the October Revolution, 3k-28k, complete set of seven, full OG, NH, mostly VF, Est. $100- $150 (Image)