Contains the correctly calibrated springs to lower pull weight and improve trigger pull quality of your Glock pistol without complicated gunsmithing or permanent alterations. Installing this kit will not disable or diminish the effectiveness of the factory safety system. Designed specifically to meet the needs of competitive shooters, this alteration is not recommended for duty pistols. Includes one each of the following springs: 4lb. reduced power striker spring, reduced power safety block spring, and extra power trigger spring. Fits all models and calibers of Glock pistols.