Sig Sauer 320X510BXR3RX2: The P320-XTEN comes standard with a 5 bull barrel, Xray3 day/night sights and an XSeries slide with front and rear serrations. Every P320-XTEN is optic-ready and compatible with the SIG Sauer ROMEO2 reflex optic which is designed to withstand the abuse the 10mm cartridge delivers. To reduce the recoil, a completely redesigned XSeries polymer grip module provides a strong stippled finish and makes shooting comfortable for any type of round. Features optic ready slide compatible with Romeo2 and Trijicon RMR (requires sealing plate); bull barrel; XSeries 10mm/45 Auto Grip Module; flat XSeries trigger with 90-degree break and Xray 3 Day/Night Sights. Includes two 15rd steel magazines. *Note - The P320-XTEN is not compatible with 9/357/40 caliber parts and accessories. Only .45 and 10mm parts and accessories are compatible with this model.