The SIG Sauer caliber X-change kit allows you to change between any of the several popular centerfire handgun calibers that your SIG P320 modular firearm is capable of shooting. It's as easy as field stripping your existing P320 pistol and re-assembling it with the components of this kit. This revolutionary design helps you get the most versatility out of your P320, by allowing you use the same firearm to shoot different common calibers.