The Apex Action Enhancement Kit for the CZ 75 B series pistols is designed to improve performance and reduce the large difference in trigger pull weight that exists between the double-action first shot and the subsequent single-action shots to approximately 2 pounds. The hammer and sear have matching Apex engineered single-action engagement surfaces that yield a clean consistent single-action style trigger break while providing a smooth stack-free double-action. The matched sear and hammer engagement surfaces require eliminate the need for any polishing or stoning. *Note: for thumb safety models only. Includes Apex Performance Hammer for CZ 75 B (thumb safety models) Performance Matched Sear for CZ 75 B (thumb safety models) Duty/Carry Mainspring Competition Mainspring Reduced Power Firing Pin Spring and a set of two Replacement Hammer Pins.