1951 Sc 1558-1561 Air sports in the USSR Scott 1590-1593

1951. Air sports in the USSR. FIRST Printing. (In 1956 the set was reprinted)
Catalog numbers: Scott 1590-1593, Standard Collection 1558-1561, Michel 1593-1596, Yvert 1576-1579.
Issued on: September 19, 1951.
Perforation: line 12½.
Printing: Offset lithography.
Colors: Multicolor.
Face value: 40 Russian kopek; 60 Russian kopek; 1 ₽; 2 ₽.
Quantity: 1,000,000; 1,000,000; 1,000,000; 1,000,000.