The 1999-S United States Mint Silver Proof 9 Coin Set includes a variety of denominations, all composed of silver with a fineness of 0.9. These coins are uncirculated and struck with a proof finish in San Francisco. Each coin comes with a Certificate of Authenticity from the U. Mint and is housed in its original box. This set is a valuable collector’s item featuring coins from the United States minted in 1999.