Up until 1971, the Mint made only Proof Sets and Mint Sets as special collectibles for sale to the public. With the introduction of the Eisenhower Dollar in 1971, the Mint offered 40% silver versions of the new Dollar in Uncirculated and Proof condition, but only from the San Francisco Mint. The Proof versions were sold in a hard plastic case inside of a brown slipcover box. The 40% alloy, the special case, and the opportunity to purchase s aingle Proof coin for the first time in more than a century proved a considerable draw, and collectors snapped up more than four million of these innovative coins.
The majority of the 1971-S Proof Silver "Ikes" remain in superb condition, however examples in the top grade of PR70DCAM are extremely rare relatiive to the total population.