Proof sets are specially minted collections of coins that are produced to showcase the craftsmanship of the U.S. Mint. The 2003 Proof Set includes a complete set of coins for that year, all struck in a higher-quality finish than standard circulation coins. This set typically features the cent through the quarter, including the 25-cent coins from the States Quarters Program, which honors each state with unique designs. Proof sets are sought after by collectors for their clarity, detail, and mirror-like surfaces.