ARO-CORE (Advanced Rifle Optic Core) is an advancement on our popular 20mm 403 and 503 series optics. ARO-CORE 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-CORE is available as a 2MOA dot only or with our Multi-Reticle System (MRS) in Red, Green, or Gold.Specifications and Features: Reticle: 2 MOA Dot & 65 MOA Circle Light Wavelength: 650nm Reticle Color: Red Parallax Free: Yes Unlimited Eye Relief: Yes Magnification: 1x Multi-Coatings: Yes Power Source: Battery Battery Type: CR2032 Battery Life (Hours): 50000 Housing Material: Durable Aluminum Surface Finish: MAO Adjustment per Click: 0.5 MOA Storage Temperature: -40~70 Working Temperature: -30~60