The Waterproof Compact Red Dot Sight is a great, tough little accessory to add to your shooting gear. The lenses are precision ground and polished to exacting geometries to virtually eliminate parallax and to provide a very clear, crisp sight picture. You get a parallax-free sighting distance of approximately 50 yds and there are five illumination settings, plus, it is fully windage and elevation adjustable and lockable. The compact sight also has a recoil resistance of at least 1,000 Gs. The compact, red dot sight is powered by a lithium CR2032 battery (included) and operating instructions are included. Also, included is an Allen wrench, a screwdriver, adjusting disk, a protective cap, a Weaver/Picatinny mount and an extra rubber sealing ring for the battery compartment.