Dagger Defense DD102R Red Dot Reflex Sight Scope - Reflex Sight Optic and Substitute for Holographic red dot Sights Red dot sight scope with four position reticles. Comes with lens cover for protection APERTURE?33mm LENGTH?82mm FIELD OF VIEW?15.8m@100m RAIL?Picatinny Includes Optic, CR2032 battery, hex wrench and lens cloth Mounts on standard picatinny rail systems Comes with lens cover for protection APERTURE: 33mm LENGTH: 82mm FIELD OF VIEW: 15.8m@100m RAIL: standard 1913 Includes Optic, CR2032 battery, hex wrench and lens cloth Mounts on standard picatinny rail systems