The ten-cent surcharge on this stamp was applied to existing stocks of the 50-cent Blackburn regular issue stamp. The surcharge, numbering 130,000 in three printings, was done locally at the Canal Zone Press, Mount Hope. The resulting stamps (Scott C-4) were first issued on December 31, 1929.
This stamp covered the new reduced airmail rate to places such as Costa Rica and the coastal cities of Colombia and was also useful for 'make-up' rates on overweight or foreign letters as well as more commonly in pairs to the United States. It is sometimes seen on first flight covers to Central and South America. However, covers not inspired by philatelic interests are rarely seen. By the time the remainders were burned in 1932, only about 116,000 copies had been actually sold.