Extremely fast, rugged and low profile, the FastFire II with a 4 MOA red-dot sight is an ideal sighting solution for pinpoint accuracy on handguns, shotguns and rifles. It simplifies the act of aiming, eliminating the need to focus on and align the front sight, rear sight and target. The aiming red dot and target are always in focus and properly aligned for the ultimate in accuracy. Integrated light sensor self-adjusts the red-dot brightness for optimal performance. Although it weighs a mere 1.6 oz., this waterproof sight has repeatedly proven its toughness on semiautomatics, slug guns, shotguns and high-power rifles. The housing is made of metal for strength and durability. Lenses are precision ground and polished to almost totally eliminate parallax and provide a clear, crisp sight picture. It is fully windage and elevation adjustable and lockable. The included plastic hood covers the light sensor and puts the unit in sleep mode when the on/off switch is set to on. Powered by a lithium CR2032 battery. Comes with a Picatinny Mount to allow mounting on just about any rifle. FastFire Mounts for mounting on other firearms sold separately.