Sig Sauer P320 Carry M18, Striker Fired, Semi-automatic, Polymer Frame Pistol, Compact, 9MM, 3.9 Barrel, PVD Finish, Coyote, SIGLITE Night Sights, Manual Safety, Optics Ready, 3 Magazines, (1) 17-Round and (2) 21-Round M18-9-CSS-MS The M18 was recently issued to all branches of the U.S. Military and was chosen as the official sidearm of the U.S. Marine Corps. The P320-M18 comes standard with SIGLITE night sights and a removable night sight rear plate.