Advanced Armament Co (AAC) Flange Indexing Direct Thread Mount Adapters enable users of modular suppressors featuring industry-standard 1-3/8-24 threaded rear sockets to convert their suppressors to A 1/2-28 and 5/8-24 direct-thread configurations. The AAC Direct-Thread Adapters are unobtrusive, low-profile designs that feature a "muzzle-brake" structure that divert gas and unconsumed propellant away from the projectile aperture and protects the blast chamber baffle from premature erosion. AAC Flange Indexing Direct-Thread Adapters feature a tool-featured flange with a square shoulder that indexes against the rear face of a host suppressor. Flange Indexing Direct-Thread Adapters should be compatible with most suppressors with industry-standard 1-3/8-24 threaded sockets. Note: These DO NOT fit Ti-Rant model silencers