The NDZ Performance P6 Polymer Grip Frame Insert Plug will fit (Gen 4-5) Glock models 17, 17L, 18, 19, 22, 23, 24, 25, 31, 32, 34, 35, 37. Please note: This plug will not fit Gen 4-5 models utilizing the OEM Removable Backstraps. The NDZ Polymer Grip Frame Insert Plug is designed to close the open cavity at the bottom of the grip, not allowing debris to enter and reach trigger assembly and firing pin. This plug utilizes a friction fit for retention. Used by LE & military worldwide.