The TRUGLO Ignite Red Dot Sight is a great sight for your new Ar-15. The 2 MOA Dot is great for precise shooting while the wide field of view keeps multiple targets in sight. The Auto-off feature preserves battery life which saves battery for your next range session. Features:2 MOA Red Dot reticle for precise aiming30mm multi coated objective lensDigital push button brightness controls8 brightness settingsRemembers last used brightness settings when powering onIncludes cantilever Picatinny rail mount (absolute co-witness with standard backup iron sights)1/2-MOA windage and elevation adjustmentsWide field of viewCNC machined from aircraft-grade aluminumUnlimited eye reliefAuto-off feature preserves battery life (4-hour idle from last button push)Nitrogen gas-filledRemovable lens cap includedBattery included (1.5V AAA)