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. This Advanced Rifle Optic features the Multi-Reticle System (MRS) that lets you switch between a 65 MOA circle with a 2 MOA dot, a standalone 2 MOA dot or standalone 65 MOA circle, all with crisp green illumination. 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.