Built as a successor to FN's proven FNS series of striker-fired pistols, the 509 is FN's premier modern striker-fired duty and defensive pistol. The 509 features a modern design consisting of a polymer frame for reduced weight and improved corrosion resistance. The pistol also features ambidextrous controls and interchangeable backstraps to accommodate a wide variety of users. The Midsize variant features a 4-inch barrel and a shortened grip for easier concealment. The MRD series features an optic cut on the slide designed to be used with FN's adapter plates and is paired with suppressor-height iron sights for proper sight co-witness. This model features an all-black color pattern and no manual safety. Two 15-round magazines are included.