This Special Edition 2002 "Quarters-Only" Proof set is a 5 piece representation of the commemorative 50 States Quarter Program. This set includes only the following 5 coins: Tennessee Ohio Louisiana Indiana Mississippi The proof coins in this set were struck at the San Francisco Mint. The term "Proof" refers to a method of manufacture and NOT the condition of a coin. Proof coins can usually be distinguished by their sharpness of detail, high wire edge, and extremely brilliant – mirror like surface. Proof coins are made from highly polished dies. The coinage blanks are also polished and cleaned. They are hand-fed into a coinage press one at a time, with each blank receiving 2 or more strikes from the dies to bring up sharp – high relief details. It is done at slow speeds with extra pressure. Finished Proofs are individually inspected and handled by gloves or tongs prior to being placed in sonically sealed plastic cases. All Proofs are originally sold by the United States Mint at a premium. Each comes in original US mint government packaging.