The Holosun ARO (Advanced Rifle Optic) Red Dot Sight is an advancement on the popular Holosun 20mm 403 and 503 series optics. The ARO features an all-new 22mm housing design that mates perfectly with Holosun magnifiers and includes an all-new 1.63" lower 1/3 co-witness pedestal mount. ARO is available as a 2MOA dot only or with the Holosun Multi-Reticle System (MRS) in Red, Green, or Gold.The HM3X line of magnifiers will allow the operator to seamlessly transition from unmagnified to 3X magnification. The Holosun HM3X features an adjustable diopter to dial in the desired focus, extremely clear glass, and very generous eye relief. Mounting options include an integrated QD mount with an optional spacer for Absolute Co-witness and Lower Co-witness. Holosun's HM3X comes in a durable Aluminum housing. FeaturesUp to 50,000 Hour Battery LifeShake Awake Technology with Last Setting RecallIP67 Waterproofing50 MOA Travle Range10 Daylight and 2 Night Brightness Settings0.866" Window Size