This is one of only 2 pattern half cents. It was struck from the regular dies in two different copper-nickel alloys either 88% copper and 12% nickel or 90% copper and 10% nickel.
Although often called die trials because of the dies used, these are really experimental pieces representing the first use of the listed copper-nickel alloys.
About 40-50 are known of which Virgil Brand owned 11.
Photo courtesy of American Numismatic Rarities.