The DUSK19 upper assembly is a pinnacle of precision engineering and design, featuring the innovative DUSK19 profile slide crafted from robust 17-4 stainless steel. This slide is available in a sleek black nitride finish or a variety of premium PVD coatings, including flat dark earth, oil-rubbed bronze and graphite gray, allowing for both aesthetic appeal and enhanced durability. Designed with functionality in mind, the slide is equipped with front and rear serrations, ensuring effortless chambering and press-check operations. For those seeking advanced sighting capabilities, the DUSK19 slide is reflex sight-ready, complete with an optic cover plate that seamlessly integrates with Trijicon RMR/SRO and Holosun 407/507/508 (excluding K models) footprints. This feature ensures compatibility with some of the most popular reflex sights on the market. Additionally, the slide is fitted with a 1/3 co-witness or suppressor height Night Fision Stealth series sight, incorporating a Tritium insert for exceptional visibility from dusk till dawn. Complementing the slide is a 416 stainless steel nitride-coated barrel, designed with the new DUSK19 profile. This non-threaded barrel features a hood pocket and lateral ribs, which are engineered to minimize bearing surface, promoting faster cycling and enhancing coating wear resistance. The DUSK19 upper assembly is a testament to cutting-edge design and functionality, offering a superior shooting experience for enthusiasts and professionals alike. Equipped for reflex sight compatibility, including a Dusk optic cover plate Nitride-coated stainless steel barrel featuring a Dusk profile Front and rear serrations facilitate chambering and press checks