Type illuminated: 20 levels brightness red and green reticle to provide maximum flexibility in different lighting conditions Focus type: Fixed Material: Aluminum alloy Easy to setup, fits any 20mm rail Elevation adjustment and view of the side of leverage Shockproof and weatherproof materials Easy to install with built-in quick detachable mount Battery: CR123A (NOT included for shipment) Operation key: Up arrow button: power on and increase brightness Down arrow button: power on and reduce glare Up and down arrow keys: off (pressing the keys simultaneously to turn off)