"The original G19X is the ultimate ""crossover,"" combining the full-size G17 frame with the shorter G19 slide to create a handgun that offers the best of both models. The GLOCK 19X V MOS Semi-Auto Pistol with Holosun HS507C Optic is the latest iteration of the legendary duty pistol that features slightly updated internals. Other than that, it's the same G19X you know and love, with virtually identical trigger pull and ergonomics. This MOS model features an optics-ready slide that comes with a factory-mounted Holosun 507C along with a threaded barrel. Other features include a reversible mag release along with front and rear serrations. Slightly updated internals Threaded barrel MOS optics-ready slide with Holosun 507C Integrated trigger blade safety Reversible mag releaseNOTE: Internal components are not cross-compatible with prior models."