monstrum tactical low profile dovetail to picatinny/weaver .22 airgun rail adaptor monstrum the monstrum tactical dovetail to picatinny rail adaptor is designed for firearms equipped with 11mm or 3/8 inch dovetail standard rails, rails typically found on air rifles or certain model .22 rimfire rifles. the adaptor's picatinny rail allows for the mounting of picatinny or weaver standard scopes, red dots, magnifiers, or other optics. the rail adaptor installs easily via the dovetail mount and one vertical stop pin. 2.8 inches at the base, the picatinny rail extends 3.9 inches allowing for more flexible optics placement and eye relief. crafted from lightweight aluminum, the rail is only 2.3 ounces in weight.