Breek Arms lineup of Outside Threaded Muzzle Devices is an affordable upgrade that gives you the option to run a flash hider or muzzle brake while utilizing our Breek Arms Castle Blast Shield as a forward blast diverter or concussion device. Simply slide the blast shield over the outside of the muzzle device and turn the blast shield on. This gives the shooter a more pleasant experience when firing especially for shorter platforms that tend to have an overbearing concussion. – Rated for 10.5'' barrels and up. – Internal Threads Disrupt Gas Expansion Resulting in Less Flash