The Echelon is the latest next-generation duty pistol from Springfield Armory with an emphasis on ergonomics and durability for striker-fired pistols while incorporating new design technologies. Related: Read our full review of the Echelon 4.0C 9mm The pistol features Springfield's Central Operating Group (COG) assembly that allows the user to change out the frame while keeping the same serialized firearm. The pistol's new Variable Interface System (VIS) also allows for over 30 different optics to be direct-mounted to the slide without a mounting plate needed. The 4.0C series features a shorter 4-inch barrel along with a smaller compact-sized frame for easier concealment in one's everyday carry. One flush-fit 17-round magazine and one extended 20-round magazine is included. Springfield's complementary double-zipper case is also included with each handgun.