The Zev Technologies© Competition Spring Kit contains a heavy trigger spring (heavier is better, as it assists with trigger pull), A reduced power firing pin spring, and a reduced power firing pin safety spring.Installation of the ZEV Technologies competition spring kit provides a lighter and smoother trigger pull for your Glock® use in conjunction with the ZEV Technologies pro connector for best performanceINCLUDED COMPONENTSA ZEV spring kit comes with one of each of the following, a 2lb Striker spring, Firing Pin safety spring, & Trigger springSPECSCaliber: 9mm, 10mm, 380, 45 Auto, 45 GAP, 357Trigger Kit Type: Trigger AccessoryTrigger Family: Trigger Accessory