These units replace the magazine base plate and retain all other factory components. They do not alter the capacity of the magazine. These units will add 1 inches additional length resulting in better control and comfort. Features: These units increase the grip length of the sub compact Glock auto pistols with out increasing their capacity These units blend with the contours and texture of the handgun giving a factory appearance They are made from high impact polymer and withstand drop tests at temperatures from -20 to 350 deg F They form the next logical finger positioning feature to provide control and comfort without sacrificing conceal ability Provides magazine identification via Mag-Track for those that rotate magazine usage