Designed to "host" (Holographic Optic Slide Top) an optic, light or suppressor in 9mm, 10mm or .45 ACP, with 4.15" or 5" barrel with threaded bushing. SS model is single-stack; DS double-stack. Magazines have extended base pads, capacity 8 or 10 rounds (SS); 9 or 15 rounds (DS). Introduced in 2017.