The twelve-cent Prexie
The twelfth President was Zachary Taylor, who served from March 5, 1849 until his death on July 9, 1850. His likeness on the twelve-cent definitive stamp of 1938 was taken from a bust in the Virginia State Capitol. Twelve-cent Prexies were only issued in sheet format.
The first release of the twelve-cent Prexie was on September 14, 1938. A total of 664,333,800 were issued through 1959.
The twelve-cent Prexie had very few single-rate usages, all fourth class.
Other single-rate solo uses involved half-ounce airmail postage to El Salvador, Guatemala, Honduras and Nicaragua.
Twelve cents was the cost of a local special delivery letter early in the period, as well as a special delivery postcard to Canada. For a short time in the late 1950's it was also the rate for third class mail with minimum insurance.
A certificate of mailing for multiple items can result in any value of Prexie being used.