The Springfield Armory® Echelon Semi-Auto Pistol with U-Notch Sight is built with excellent ergonomics and built for harsh conditions. This striker-fired pistol features a COG (Central Operating Group) stainless steel chassis with fully-ambidextrous controls. A revolutionary VIS (Variable Optics System) utilizes a series of movable pins, which allow for a wide variety of low-seated, direct-mounted optics. The rear sight channel is cut separate from the optics plate and uses a U-notch rear sight in conjunction with a tritium-dot front sight.