This coin is a 2017 Kennedy Half Dollar, minted at the San Francisco Mint, with the mint mark 'S'. It is part of the Kennedy Half Dollar series and is a proof coin, which means it was minted using a special process to produce a high-quality finish with mirrored surfaces and sharp details. The coin has a denomination of 50 cents and weighs approximately 11.34 grams. It features the traditional Kennedy design on the obverse, showing a profile of President John F. Kennedy, and the reverse displays the Presidential seal. The coin is composed of a copper-nickel clad copper material. With a diameter of about 30.6 millimeters, this 2017 proof Kennedy Half Dollar is a noteworthy collectible within the series, especially considering its unique minting characteristics. It's important to note that the production type indicates no mintage figure has been provided, which can denote either a special, limited issue or potentially a reporting error for that year. This coin represents not only a piece of currency but also a segment of American history and numismatic interest. As a collectible item, its value would depend heavily on its condition, packaging, and the current market demand for proof coins, particularly those from the Kennedy series.