Up for sale, is a new - never mounted/used AAC Blackout Flashhider. This is still in original packaging with RockSett. Rainier Arms™ | Browse | Muzzle Devices | AAC 5.56MM Blackout 51T Flash Hider Details: 51T Ratchet Mount - Thread Pitch 1/2 x 28 TPI. Available in Renton to Redmond area, or will possibly ship under right condition. Asking $85 OBO Cash only.