The Flash Hider-QD is designed to mitigate flash when unsuppressed. The Flash Hider-QD 556 is compatible with HX-QD series (556k, 556, 762, 762 Ti and Magnum Ti) and FLOW series (556k, 6k, 762 Ti) suppressors. This flash hider is only compatible with VENTUM series suppressors when combined with the HUX HUB-Adapter. NOTE: Larger caliber mounts are NOT compatible with smaller caliber suppressors. Smaller caliber mounts ARE compatible with larger caliber suppressors.