This set contains the burnished versions of the proof versions of the four different denominations of the American Platinum Eagle coin issued in 2006. The coins were struck by the West Point Mint and have a W mint mark, unlike the bullion coins which were struck by the Philadelphia Mint and have no mint mark.
The proof version is the first in the three-year Branches of Government Series dedicated to the three branches of U.S. government, and is dedicated to the Legislative Branch. The reverse design of the coins depicts a seated "Legislative Muse" holding a book, flanked by two eagles perched on columns representing the bicameral legislature of the United States Congress.
The "burnished" version of these coins are not proof but an enhanced Brilliant Uncirculated grade with specially smoothed surfaces.