The Monstrum Tactical 30mm Scope Mounted Picatinny Rail Mount/Adaptor is designed to attach to 30mm rifle scope tubes, allowing you to mount a backup sighting system atop your rifle scope. The 30mm ring fastens around 30mm scope tubes installing easily via two set screws and the included hex key. The Picatinny rail mount will accept any standard Picatinny red dot/reflex sight or other optics. Crafted from 6000 series aircraft grade aluminum alloy, the rail mount weighs only 2 ounces. The rail mount is 2 inches in length.