The U.S. Mint recently revealed that they were selling 2019 W Pennies as a part of their 2019 proof set, which can be found here at their website: https://catalog.usmint.gov/proof-set-2019-19RG.html . These pennies produced from the West Point Mint are special because the West Point Mint is known for producing commemoratives, such as the 50th anniversary of the moon landing, or other special collector's coins, such as the American Eagles. They normally don't produce standard coinage such as pennies. Prior to 2019, West Point did not make pennies. They did, however, produce a commemorative 50th anniversary of the Roosevelt dime in 1996. In 2014, they produced a W Kennedy Half Dollar to commemorate the 50th anniversary of the Kennedy half Dollar. In 2015, they produced more W dimes along with W dollars to commemorate the March of Dimes. This is the first time they are producing pennies.

These pennies have the standard composition of post-1982 circulating ones. They're 97.5% zinc, and 2.5% copper, making a copper-plated zinc penny. In terms of design, they are identical to the standard Union Shield penny.

Aimed towards collectors, these pennies will be added to traditional mint sets. This addition is similar to the addition of the 1996 W dime in the 1996 mint sets - they come as a bonus, and not as extra charge. They will be produced in three finishes along with their mint sets: an uncirculated penny with an uncirculated set, a proof penny with a proof set, and a reverse proof penny with a silver proof set. All other coins in the sets will contain an S mintmark. The W pennies won't be for sale individually, unless you buy from a third-party dealer.
More details about each type of penny: The uncirculated penny is not as shiny as the proof penny, but they are minted with special dies and with above-average force, resulting in a beautiful look.
The proof penny has sharp, frosted relief and brilliant mirrored backgrounds, resulting in a cameo look. The reverse proof penny has the opposite features of the proof: it has brilliant mirrored designs and frosted backgrounds. This creates high contrast, and is exceptionally pleasing to the eye. All three of these types will be packaged in clear United States Mint plastic wrap.
Overall, the 2019 W pennies are a unique addition to any collection, whether it's big or small. Because these pennies are probably limited edition, getting another one of these pennies in the future may become expensive, as these pennies are only produced in mint sets. This unique coin, whether uncirculated, proof, or reverse proof, will be a very nice and appealing addition to your collection.
References:
Proof set 2019. (n.d.). Retrieved March 8, 2019, from https://catalog.usmint.gov/proof-set-2019-19RG.html