Springfield Armory Echelon 4.5F with Aimpoint COA Optic 9mm Luger 4.5in Black Melonite Pistol - 20+1 Rounds - Engineered with superior ergonomics and built to withstand the harshest conditions, the Echelon 4.5in 9mm handgun sets a new standard for modern, striker-fired duty pistols. The Echelon with COA optic is built around a truly modular platform and delivered optic-ready with the Aimpoint COA red dot installed from the factory. With a host of patent pending features, this modular pistol is designed around a robust stainless steel chassis. Fully ambidextrous, the Echelon features a U-Dot sight system for fast target acquisition. 1:10in Twist ; Sights: Tritium/Luminescent Front, Tactical Rack U-Dot Rear; Slide: Billet Machined, Melonite Finish, Optics Ready; Barrel: Cold Hammer Forged Steel; Captive Recoil System; Black Polymer Frame with Medium Grip Module; Central Operating Group: The all-new Central Operating Group is self-contained and serialized, providing a robust housing for the patent pending operating system.; Variable Interface System: By utilizing a set of movable pins, the Variable Interface System on the Echelon achieves a low, direct mount optics solution for improved sight picture and intuitive alignment.;