1931, 10k-1r, complete set of six in blocks of four, including 20k light red, all with comb perforation, block of 15k folded once along vertical perforation, post office fresh quality unit, full OG, NH, VF (Image)

1931, Airship over Red Square, 20k light red, top left corner sheet margin unfolded block of four, lower left stamp with white vertical stroke at the bottom inscription (position 11), full OG, NH, VF (Image)

1931, Airship over the Arctic Region, 50k dark brown, right sheet margin unfolded block of four, upper left stamp with a dot inside ''o'' at the top inscription (position 44), full OG (no gum on margin as often), NH, VF (Image)

1932, Airship over the Dnieper Dam, 15k gray black, engraved printing, perforation 10 1/2, very well centered with intact perforation, full OG, LH, VF and rare in sound condition (Image)

1932, Airship over the Dnieper Dam, 15k gray black, perforation 14, unfolded block of four, full OG, NH, VF (Image)

1932, Airship over the Dnieper Dam, 15k gray black, left margin imperforated single, bright gum and post office fresh, full OG, NH, VF, J. Stolow guarantee hs on reverse (Image)

1932, Airship over the Dnieper Dam, 15k gray black, four-side margins imperforated single,flawless quality, full OG, NH, VF, J. Stolow guarantee hs on reverse (Image)