Five cents postage would pay the Universal Postal Union Rate for a half-ounce letter from the United States to any signatory nation anywhere in the world during the lifetime of the First Bureau Printings. The 5-cent stamp was printed to pay this rate.
The first two printings are found in brown colors somewhat duller than the 4-cent stamp. The third printings were produced in dark blue. The unwatermarked printing can be found in a vertical format, imperforate horizontally. This error is extremely rare.
This stamp is fun to collect on cover to exotic destinations such as Burma, Tahiti, and Madagascar, to name but a few of the U.P.U. signatory countries.