4-Trigger Spring KitThis CZ-452 Deluxe Spring Kit fits ALL 452 models. The 4 different trigger springs in the kit will allow for a selection of different trigger pulls. Simple and easy to install, it allows you to safely adjust the trigger pull weight to suite most styles or needs. Works great with the CZ adjustable sear kits that we offer. also included is an extra power firing pin spring to help improve primer ignition and decrease lock time. The extra power spring is a big improvement over the factory spring. It decreases lock time and provides a very positive primer strike.