Ade Advanced Optics RD3-009-2 Red Dot Sights Waterproof/Shock/Fog Resistant Lenses are precision ground and polished to exacting geometries to virtually eliminate parallax and to provide a very clear, crisp sight picture Fully windage and elevation adjustable and lockable; Unlimited Eye Relief 5 MOA. 5 Illumination Settings Powered by a lithium CR2032 battery(Included)