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" additional length resulting in better control and comfort. These units increase the grip length of the Sub Compact Glock AutoPistols 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 F to 350 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