Sig Sauer Fire Control Unit, Fits P320, Titanium Nitride Finish, Gold, Compatible with 9mm/40 S&W/357 Sig, Skeletonized Flat Blade Trigger 8900160 From the beginning, the P320 was built to be a pistol that could adapt to meet the user's specific needs. From grip modules and magazines to custom slides, barrels, and optics, the P320 can be configured in thousands of different ways to make your P320 unique and exactly the pistol you are looking for.