The 4-cent SEATO stamp was issued on May 31, 1960, in Washington, DC. The central design features the emblem of the Southeast Asia Treaty Organization (SEATO) Conference in Washington, DC, May 31-June 3. SEATO was a regional-defense organization that came into force on February 19, 1955, in order to protect the region from communism. The organization was disbanded in 1977.
Designed by John Maass, the stamp was 0.85 by 0.98 of an inch in dimension, arranged vertically. Initial printing of 120 million stamps was authorized.
Postal Bulletin (April 7, 1960).