The HGMR Reflex Sight is designed to quickly attach/detach from standard size handgun/rifle with Picatinny/Weaver rails. It features a tubeless design with a 40mm reflex lens aperture that provides a wide field of view, suitable for rapid-firing or the shooting of moving targets besides normal shooting. It has multi-reticle (4 patterns) installed. It is parallax free and has unlimited eye-relief. Allen head screw type for windage and elevation click adjustments, with locking screw. Built-in mount (integrated rail) for standard bases, no need to re-zero when mounting the dismounted sight. Very light weight, waterproof and shockproof. Low power consumption for long battery life. It is backed by Osprey's industry leading no-nonsense lifetime warranty.Lifetime warranty; contact (470)274-5295 for warranty questions