The Sig Sauer Caliber X-Change Kit allows you to select any of several centerfire calibers for use with your Sig Sauer firearm. Just disassemble the pistol and reassemble it with the X-Change Kit's Barrel, Slide Assembly, Grip Module, and Magazine. Includes Siglite Night Sight Set as well. IncludesComplete slide assembly with Nitron finishBarrelSIGLITE night sightsGrip Module(1) 10-round steel magazine