Sig Sauer Fire Control Unit, Fits P365, Titanium Nitride Finish, Gold, Compatible with 9mm/380 ACP, Flat Trigger 8900164 The P365 Custom Works Fire Control Unit (FCU) brings an unprecedented level of customizability and personalization to the micro-compact carry platform. From grip modules, magazines, custom slides, barrels, optics, and accessories, you can configure your P365 in thousands of different ways to personally customize your pistol to your specific carry needs.