Dead Air keymo adapter (hub thread pattern) with 9mm bore 1/2x28 keymicro flash hider, new production, unused - $180. Silencerco Charlie pattern ASR adapter with 22 bore 1/2x28 closed tine flash hider, new production, unused - $140. Griffin Armament H900 Plan A adapter (hub thread pattern) with 9mm bore 1/2x28 minimalist flash hider, lightly used -$60.