Thailand. (South Africa - Horseshoe Route). 1940. Air Mail envelope addressed to Michigan bearing SG 243, 50s orange and black (pair) tied by Bangkok GPO date stamp '4th Sept 40', endorsed 'By B.O.A.C.' with bilingual 'Opened by Censor' label.
This letter was carried by B.O.A.C. on the 'Horseshoe' route to Durban, South Africa where censor label was applied and then carried by ship via London to the United States.