A reflex sight is a type of optical sight used on firearms, allowing shooters to aim quickly and accurately. It features a lens that reflects a reticle, usually a dot or crosshair, which appears superimposed on the target. This design enables users to keep both eyes open, improving situational awareness while aiming. Reflex sights are commonly used in various shooting sports, hunting, and tactical applications. They are often mounted on rifles, shotguns, and handguns. Popular brands include Aimpoint, EOTech, and Trijicon, each offering different models with varying features like brightness settings and reticle styles.