These Grip Extensions replace the magazine base plate and retain all other factory components. They do not alter the capacity of the magazine providing better comfort and control by adding approximately 1/2 inch of gripping surface. An optional filler piece is provided for For Glock models with a semi-circular cut-out in the lower front area of the grip body. This filler piece allows for installation of the PG-19 on all Mid and Full Size For Glocks. Fits Models 17,18,19,22,23,24,25,31,32,34,35,37,38 - Full Metal Lined Magazines Only. Key Benefits ? 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 provide comfort by increasing the length of the grip 1/2 inch over stock dimensions. ? They provide an easier means of manually extracting the magazines. ? Provides magazine identification via Mag-Track? for those that rotate magazine usage.