In 1983 the U.S. Mint introduced the Prestige Proof Set from the San Francisco Mint. They are sets that included the 6 regular issue coins (the Cent through the Half Dollar) and then the special Commemorative coin(s) of that year.
This is the 1991 Prestige Proof Set. It Includes the 1991 Mount Rushmore Dollar and Buffalo Clad Half Dollar.
The coins in the Prestige Proof set are presented in a deluxe plastic lens and displayed in a collector album, with a display box and a Certificate of Authenticity (COA).