The Holosun ARO Multi-Reticle Green Dot Sight builds on the success of the 20mm 403 and 503 series, introducing a refined 22mm housing and a new 1.63″ lower 1/3 co-witness pedestal mount. Shake Awake technology conserves battery life by deactivating the LED when idle and instantly reactivating it with the slightest motion. Powered by a CR2032 battery, the ARO delivers up to 50,000 hours of operation at mid-level brightness. With 10 brightness settings, including two for night vision, and a durable aluminum housing with a corrosion-resistant finish, this optic is built for rugged reliability.