SilencerCo Hybrid ASR Flash Hider, 13.5x1LH (Sig MPX), 9MM AC1561 The ASR Flash Hider is compatible with SilencerCo's 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 schedule. The patent-pending resonance suppression effectively eliminates the tuning-fork effect common with competing 3-prong Flash Hiders.