The Springfield Armory Echelon 4.0C COA 15-Round packages ultimate enclosed-emitter red dot precision within a compact, carry-optimized framework tailored for capacity-regulated jurisdictions. Built directly around the serialized, self-contained Central Operating Group (COG) stainless steel chassis, this defensive 9mm scales down to a compact frame module to maximize everyday concealment potential without yielding any of the platform's robust service-grade lifespan. The defining mechanical feature of the EC9409B-COA-15 configuration is its factory-integrated Aimpoint® A-CUT slide profile. Rather than relying on traditional multi-piece adapter plate sets, this slide utilizes a deep wedge-lock configuration that direct-mounts the included Aimpoint® COA enclosed red dot sight straight to the steel slide. Eliminating transitional mounting plate hardware significantly reduces height-over-bore metrics and isolates the mounting screws from shear strain during cycling strings. Outfitted with black serrated tactical backup irons that co-witness seamlessly through the window, it ships from Geneseo with two 15-round flush steel magazines.