Durability and dead-on accuracy have made Troy Industries Folding BattleSights the choice of Special Ops and tactical users worldwide. The TROY 45 Degree Folding BattleSights fold compactly to both sides of the rifle. With an ambidextrous sight base, TROY 45 Degree BattleSights work seamlessly with magnified optics. Easy to install and deploy, these sights position apertures at factory height. A stainless-steel cross-locking system ensures sight remains upright and zeroed under extreme combat conditions. Notes: Sight is designed to work on same plane rail systems only. Will not work with a railed gas block that is higher or lower than the receiver.Troy Industries makes two sights; standard, medium and micro. The measurement to the center of the standard aperture is 1.36". The measurement to the center of the micro aperture is 1.16". The standard sights are meant for Mil-spec top rails and the Micros are meant for the enhanced weapons such as the IAR, Robinson Armament X...