The 1978-S U.S. Proof Set is a six coin set featuring uncirculated coins composed of copper. This set was minted in San Francisco by the United States Mint, making it a valuable collector's item for those interested in American coins. The set includes coins struck in proof quality, adding to their visual appeal and desirability among numismatists. With its pristine condition and historical significance, the 1978-S U.S. Proof Set is a sought-after addition to any coin collection.