This version of the A2 Bird Cage Flash Hider makes a 14.5” barrel a legal length of 16” when pinned and welded over (one hole for pinning and welding located on the bottom), or it can be threaded onto any standard 16″ barrel. Threaded 1/2” x 28 T.P.I., with Black Phosphate finish. Overall length is 2 ¼”. Should be installed with a Crush Washer for proper port “timing”.