The Apex Tactical Duty/Carry Action Enhancement Kit was designed to provide the J-Frame revolver owner a smooth, consistent 9 lb trigger which is down from the factory rating of over 12 lbs. Notes: This kit is engineered to be drop-in and should require no further gunsmithing however armorer or gunsmith installation is always recommended. Works with all modern center fire J-Frame revolvers with the frame mounted firing pin. Kit Includes: Apex Rebound Slide SpringApex Main SpringApex XP Firing Pin Kit