The United States Mint Proof Set includes coins from the years 1999, 2002, 2003, and 2004, all in a proof strike type. These sets are uncirculated and come with a Certificate of Authenticity from the U.S. Mint. The coins are minted in San Francisco, United States, making them a valuable addition to any coin collection. Each set contains a variety of coins showcasing the style and craftsmanship of American coinage from the early 2000s.