The former Harry W. Bass Jr Research Foundation example. Photo courtesy of David Cassel.
Examples are known in the following compositions:
Nickel J644/P716. About half a dozen are known.
Copper J645/P717 with at least 3 known, 2 of which, the former Bass and Garrett pieces, are in the Cassel collection and the third is in the Simpson collection.
Aluminum J646/P718 About a half dozen are known. These usually show corrosion. The 2 in Dave Cassel's collection had significant amounts of silver in the alloy.
The listing of this in silver J643/P715 has been discredited by the research of David Cassel.
David Cassel's book on Postage Currency Patterns is now available. For more on this, click here.