*The T10 Red Dot automatically turns on when it is moved and will auto shut off if not moved for 1-3mins.*1 CR2032 battery will last up to 50,000 hours of use with a crisp 2 MOA Red Dot with 10 brightness settings for visibility in all light conditions.*The T10 is a one-piece Aluminum construction that is Fog Proof, Shock proof, Water proof up to 3 meters.Red dot sight for ar15Rugged and Reliable Red Dot (Destruction Test)