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. Specifications and Features: CALIBER: 9MM FCU MATERIAL: STAINLESS STEEL GRIP MODULE: COYOTE XMACRO POLYMER SLIDE MATERIAL: STAINLESS STEEL SLIDE FINISH: COYOTE CERAKOTE MAGAZINE CAPACITY: 21 ROUNDS SIGHTS: XRAY3 DAY/NIGHT SIGHTS | ROMEO-X SIG-LOC (CIRCLE DOT) TRIGGER: FLAT STRIKER FIRED OVERALL LENGTH: 8 in OVERALL HEIGHT: 8 in OVERALL WIDTH: 1.4 in BARREL LENGTH: 5.1 in SIGHT RADIUS: 6 in WEIGHT W/MAGAZINE: 24.8 oz