Monaco 371a-380a pairs (371-390) mlh

Monaco 371a-380a pairs (371-390), lightly hinged, $103.15. Michel 538-557. Early & modern postal transport surcharged with a new value, 1956. Carrier pigeon, Sikorsky helicopter; Old railroad engine, modern locomotive; Old monoplane, Comet airliner; Steam automobile, Sabre sports car; da Vinci's flying machine, Rocket; Post rider, motorcyclist.