The Pearce Grip Extension for the Glock 9/40/357/45 GAP is an accessory that enhances the versatility, look, and feel of the gun. This unit adds capacity to Generation 4 Sub-Compact, Mid, and Full Size Glock high capacity magazines. This magazine extension replaces the original floor plate and internal locking plate and adds two rounds to a 9mm; two rounds to a 40SW and 357SIG, and one round to a 45GAP magazine. This unit will not fit the 10mm or 45ACP models. The Pearce Grip Extension has been designed to flow seamlessly into the design of the handgun itself, reinforcing the aesthetics of the classic Glock look. · Gun Fitment –Glock Generation 4 Models 9/40/357/45 GAP · Easy to install · Enhances versatility, look & feel · These units alter the capacity of High Capacity Full Metal Lined Glock magazines · These units add two rounds to the 9mm, two rounds to the 40SW and 357SIG and one round to the 45GAP models · Made from High Impact Polymer and withstand drop tests at temperatures from -20 F to 350 F