Wolff Shooter's Packs contain reliable springs which provide a great improvement in the overall trigger pull and hammer function. Installation requires disassembly and reassembly of the revolver. Kit Includes: Reduced power hammer spring 19 lb. pack includes 40 Ounce Wolff designed reduced power trigger spring17 lb. pack includes 30 Ounce Wolff designed reduced power trigger springExtra power base pin latch spring Notes:These springs reduce and smooth out trigger pull for competition trigger pull performance. Installation requires disassembly and reassembly of revolver. New Model Vaquero's with small frame (NV Series) and Blackhawk 50th Anniversay models with XR-3 grip frame and internal hammer lock use the same internal springs as the older Ruger single actions EXCEPT for hammer springs. This spring pack does NOT include a hammer spring for these newer models.