The coin in question is a 1971 San Francisco minted Lincoln Cent, specifically part of the Memorial Reverse series. This particular coin is notable for being a Proof issue, which means it was struck with a higher level of detail and polish compared to regular circulation strikes. Made from brass, the coin has a diameter of 19 millimeters and weighs approximately 3.11 grams. It carries a nominal denomination of one cent (1¢) and features the iconic design of Abraham Lincoln on the obverse, while the reverse showcases the Memorial design. With a total mintage of 3,220,733 coins produced, this 1971 Proof Lincoln Cent is a collectible piece for numismatists and coin enthusiasts. Being struck in San Francisco, it bears the 'S' mint mark, distinguishing it from coins minted in other locations. As a coin that exemplifies the artistry and history of American currency, it holds both intrinsic and collectible value within the realm of United States numismatics. Given its characteristics and the specifics of the Proof minting process, this coin is a wonderful addition to any collection, especially for those focused on Lincoln Cents and commemorative issues from the era.