Convert your Glock into a .22 for affordable target practice with the Advantage Arms® .22 LR Conversion Kit with One 10-Round Magazine for Gen 3 Glock 20, 20SF, 21, 21SF Pistols. This kit converts your Gen 3 Glock 20, 20SF, 21, or 21SF pistol down to .22LR to save money and as a way to introduce beginners to the world of shooting. This kit includes a slide, barrel, guide rod assembly, range bag, and a 10-round magazine. Fits Gen 3 Glock 20, 20SF, 21, and 21SF pistols.