The Flash Hider-QD 556 is designed to mitigate flash when unsuppressed. - Muzzle device length is 2.3 inches length added to the barrel is 1.7 inches (on barrels with 0.6 threads) - The Flash Hider-QD 556 is compatible with the HX-QD series (556k 556 762 762 Ti and Magnum Ti) and FLOW series (556k 556 Ti 6k and 762 Ti) suppressors. This flash hider is only compatible with VENTUM series suppressors when combined with the HUX HUB Adapter.