This is a 1964 Mint Proof Set still sealed in the flat pack packaging. From 1936 to 1972, Proof Sets from the US Mint contained the cent, nickel, dime, quarter, and half dollar coins. As the Kennedy Half Dollar was first issued in 1964, this Proof Set is highly sought after. From 1965 to 1967, the US Mint did not issue Proof Sets, instead offering Special Mint Sets. When the Proof Sets were once again offered in 1968, the packaging was changed to a rigid holder in a box. Coming from the first year that Kennedy Half Dollars were struck, this 1964 Mint Sealed Proof Set Flat Pack is an incredible piece of numismatic history.