Good things come to those who wait, and while the Echelon isn't the first polymer pistol to feature a modular design, night sights, and optics mounting system—it might be the BEST. Like the SIG P320, the Echelon is built around a serialized chassis that Springfield calls the Central Operating Group—essentially the "skeleton" of the gun—which can be customized with small and medium grip frames. This allows you to effectively turn the Echelon into a compact or subcompact gun with optional slide/frame combos (sold separately, and available from Springfield soon). But unlike other serialized chassis out there, Springfield's Central Operating Group is considerably sturdier and more rigid, providing an incredibly robust housing for the operating system.