This slide is for 9mm barrels only and is not compatible with .40, .357, or .45. This product is the SLIDE ONLY, (barrel and recoil assembly are not included). Factory replacement Slide Assembly for the P320 X-COMPACT through X-FULL size pistols. For use with the standard 9MM, 4.7" non-threaded, or 5.5" threaded barrels. Features: Optic ready. Compatibility: ROMEO1-PRO, ROMEO2, Delta Point Pro, and RMR (requires sealing plate) footprint. XRAY3 Day/Night Suppressor height sights. Durable Nitron Black Finish. Removable optics plate with top accessible screws.