If you shoot a lot, sooner or later you will have a problem with a stock firing pin. Precision strikers improve performance and service life, tighter tolerances than factory. CNC-machined from solid 17-4 PH stainless steel billet, the low temperature vacuum PVD (Physical Vapor Deposition) coating creates a durable barrier against wear and tear. Strikers are individually hand inspected for accuracy. No gunsmith required. Replacement striker for Glock 9mm/40 S&W, Generation 3&4 (excluding Glock 43).