ARO (Advanced Rifle Optic) is an advancement on the popular 20mm 403 and 503 series optics. ARO features an all-new 22mm housing design that mates perfectly with our magnifier series and an all-new 1.63 lower 1/3 co-witness pedestal mount. ARO is available as a 2MOA dot only or with our Multi-Reticle System (MRS) in Red, Green, or Gold.Specifications and Features:Magnification: 1xEye Relief: UnlimitedWeight: 3.38 ozBattery Size: CR2032Reticle: 2 MOA Red Dot