OLOSUN ARO ENCLOSED 2MOA RETICLE RIFLE SIGHT RED W/HM3X ARO (Advanced Rifle Optic) is an advancement on their popular 20mm 403 and 503 series optics. ARO features an all-new 22mm housing design that mates perfectly with their 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 their Multi-Reticle System (MRS) in Red, Green, or Gold. The HM3X is an aluminum bodied 3X magnifier designed for use in conjunction with a red dot sight. The HM3X is feature-packed and includes a quick release, ambidextrous, flip-to-side Picatinny rail mount. Holosun includes a spacer with the HM3X that provides compatibility with absolut Mfg: Holosun