Slide Integrated Expansion Chamber with 3.7 Barrel – Aggressive FUSE Slide Serrations – Equipped with ROMEO-X SIG-LOCTM Compact Circle Dot – Fully Enclosed Sealed and Gas-Purged Optic System and Assembled in the USA – Mounts from Underneath the Pistol Slide Utilizing the SIG-LOCTM Mounting System for the Strongest Lockup in the Industry – Side Battery Allows a Low Deck Height and a Standard-Height Iron Sight Co-Witness – Polymer Grip Module with 1913 Accessory Rail – Interchangeable Small Medium and Large Backstrap Included – X-RAY 3 Day/Night Sights – (1) 17rd (2) 21rd Steel Magazines – CALIBER 9MM – FCU MATERIAL STAINLESS STEEL – GRIP MODULE POLYMER – SLIDE MATERIAL STAINLESS STEEL – SLIDE FINISH NITRON – MAGAZINE CAPACITY 17 OR 21 ROUNDS – SIGHTS X-RAY3 DAY/NIGHT SIGHTS – TRIGGER FLAT-FACED STRIKER FIRED – OVERALL LENGTH 7.2 in – OVERALL HEIGHT 5.7 in – OVERALL WIDTH 1.4 in – BARREL LENGTH 3.7 in – SIGHT RADIUS 5.5 in – WEIGHT W/MAGAZINE 23.4 oz