Holosun Paralow HS503C Circle Dot Sight, Black, 133x54x72mm is a small, compact red dot sight with the option of dot only or dot with circle reticle pattern. Employing new LED technology, the life time for one CR2032 battery can be up to 5 years. The sight may be installed on various firearms such as shotguns, pistols, rifles, air rifles and crossbows . Features parallax free with unlimited eye relief. Minimize vision obstruction with push button controls and streamlined houseing design. Operates on both solar and battery power supplies. You can easily switch between circle dot and red dot reticles. AR riser included which is adaptable to Picatinny and Weaver rails. CNC machining with T6061-T6 aluminum housing.