This is the Smith & Wesson M&P FPC .40 S&W 20-round extended magazine. 

Don’t settle for fewer rounds when you can run this reliable factory 20-round magazine in your FPC and M&P40.

The stainless steel body features a corrosion-resistant finish that delivers superior durability. Thanks to the anti-tilt polymer follower and high-tensile steel spring, it’s equally reliable. 

On top of it all, you’ll find side-facing numbered witness holes and a polymer grip sleeve. What more could you ask for? Whether you’re using your FPC as a truck gun, home defense gun, or for plain old fun at the range, the more rounds you can have, the better!

Since the FPC features in-stock magazine storage for up to two additional magazines, you might as well buy a few!