1939 MARCH 27: MANILA to NEW YORK
Research Council official mail franked with 10c x 10 Fort Santiago O.B. issues for proper 1 Peso Single Clipper Air Rate as endorsed in violet.

Largest Recorded Use on Cover
1935: MANILA to WASHINGTON
Bureau of Commerce official mail franked with 10c x 2 Fort Santiago, 2c x 2 Rizal and 8c Pearl Fishing O.B. issues for proper 32c Double Outbound Registered Rate to the U.S. (12c Postage + 20c Registry Fee).