Meprolights durable, aluminum-bodied Mepro RDS reflex sight features a crisp 2.0 MOA red dot and a large clear crystal display window for greater FOV with both eyes open. Four brightness settings allow the shooter to adjust to changing light conditions. The technologically advanced on-off sensor shuts the optic off to preserve battery life when no movement is detected. One common AA battery provides thousands of hours of use. It mounts to any Picatinny rail and is compatible with NVGs and magnifying scopes.