Proof sets are the most popular gift item produced by the United States Mint. Proof sets are specially prepared sets of special coins made for collectors by the United States government. These coins are legal tender but were never meant to be used in circulation. The coins are struck from dies that have been prepared and polished just for this purpose. The planchets (the discs of metal the coins are struck on) are polished to a mirror finish. Everything is done to make these coins better than the best of the regular business strike coins we use in our daily life; to make them a presentation grade item.
The sets contain one of each circulating coin issued that year. Most proof coins are struck at the San Francisco Mint and have that mint mark but there are exceptions. In addition, in some years special proof sets are prepared with the clad coins being struck in silver and Prestige Sets are sometimes prepared that not only have one of each circulating coin but one of each commemorative silver coin as well. Formal Proof Sets have been offered by the Mint in most years since 1936 and are the collecting choice for those who demand coins that are more than merely perfect.