DUSK19 slide with 17-4 stainless steel, black nitride or PVD finish; Optic cut for RMR/SRO and Holosun 407/507/508 (Non-K); Front and rear slide serrations; Night Fision Stealth sights with Tritium insert; 416 stainless steel barrel, threaded or non-threaded; Hood pocket and lateral ribs for faster cycling; CCS frame with 19deg grip angle; Interchangeable flat and rounded backstraps; Flared magwell with textured toe kick; Flat enhanced trigger with 30% reduced peak force