Seal 1971 United States Mint Set in Original Government Packaging. This unopen 1971 Mint Set included a total of eleven different coins, an increase of one coin compared to the prior year. This added coin was issued since the Kennedy Half Dollar was struck at two different mint facilities that year. Notably, this was the first year that the denomination was struck in copper nickel clad composition, after having been struck in 40% silver from 1965 to 1970. The coins of the annual mint set were the P-D-S Lincoln Cent, P-D Jefferson Nickel, P-D Roosevelt Dime, P-D Washington Quarter, and P-D Kennedy Half. The coins were packaged similarly in two cellophane packs with colored stripes, red for Denver and blue for Philadelphia and San Francisco. The packs were placed between two cardboard inserts and put into a white envelope marked “1971-U.C.” with Treasury Department return address.