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 integrated compensated slide assembly with Nitron finish3.1" BarrelSIG SAUER X-RAY3 day/night sights (3-dot Tritium system)Removable sight plateXMACRO Grip Module featuring a true 1913 Picatinny accessory rail(2) 17-round 9mm steel magazines