Overprint size 16.5 x 3.0 mm
using printer's cliche and ink. 

This overprint type is one of the three Tagle overprints known as the 1938-40 Bureau Imitations as they are somewhat similar to Scott # O28 to O36, the Bureau Official Issue of 1938-40. 

Overprint Color: Violet Black

All Top Horizontal Overprints

This Tagle overprint is very close in appearance to the 1938-40 Bureau issued Officials. Both have similar overprint length and serifed letter B. The differences are the height of the letters: 3.5 mm for the Bureau issues and only 3.0 mm on the Tagle issue and the Bureau issue letter O is not round while the Tagle issue O is round. To date, no Bureau issue of 1938-40 has been found with a Tagle overprint on the same value or issue.
1939 FIRST FOREIGN TRADE WEEK

449

450

451

1939 AUGUST 18: MANILA to SAN FRANCISCO
Franked with First Foreign set with Type C "O.B." overprints.
Registered, proper rate at 1p-20c. Backstamped SAN FRANCISCO / AUG 24.
1939 FIRST AIR MAIL EXHIBITION

C-57

C-58