To help alleviate a national coin shortage in the mid-sixties, caused in part by the popularity of the Kennedy half dollar, the U.S. Mint decided not to strike Proof Sets for collectors. Instead, it struck Special Mint Sets at the San Francisco branch, leaving off the "S" mint mark. Every coin in these 3 sets is struck on specially polished blanks, and each set has been hand selected for quality and eye appeal by Littleton's team of experts. The 1965 set comes in a soft plastic holder, while both the 1966 and 1967 sets come in hard plastic holders. Don't miss your opportunity to purchase all 3 of these Special Mint Sets for one low price!