SilencerCo AC1561 ASR Flash Hider Black Steel with 13.5x1 LH tpi Threads for 9mmThe ASR Flash Hider is compatible with ASR (Active Spring Retention) Mounts. The ASR (Active Spring Retention) Mount is a quick attach detach system for almost all SilencerCo suppressors. The simple one hand on, one hand off mounting system is compatible with all ASR Muzzle Devices to promote ease of transfer from one silencer to another. Once shouldered, the locking ring ensures the silencer won't rotate or work itself loose under a heavy firing