In the world of Glock®customization, the Glock®G21 seems to get short-shrift, since everything's made for either the 9mm or .40 S&W variants of popular Glock®handguns. Fans of the big-bore .45 ACP are left in the dust with their OEM models, but the Marksman V4 Slide designed for use in Gen 3 models of the G21 allows owners of these guns to step up with a clean, custom look. Each Marksman V4 G21 Slide is machined from 416 stainless steel in order to ensure long-lasting performance, and the rear of the slide is milled to accept a Trijicon RMR or a Holosun 507 red-dot sight. The slide is finished with a DLC PVD treatment, and other highlights include enhanced serrations for more positive manipulation of the slide, as well as a clean, attractive finish. The Marksman V4 G21 Slide is designed for use on Gen 3 Glock®G21s or P80 PF45 handgun frames only.