Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Soviet Union - 1935, Moscow-San Francisco Flight, red surcharge 1r on 10k dark brown, position 25 of 25-stamp setting, full original slightly disturbed gum with very slight foxing, VF, Soviet Philatelic and several other guarantees, C.v. $500, Est. $400-$500 , Sc. #C68