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 the 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. FEATURES: Internal Threads Disrupt Gas Expansion Resulting in Less Flash Design: 3FO - 3 Prong Outside Threaded Flash Hider Outside Thread: 13/16 x 16 TPI Material: 4140 Prehard S Mfg: Breek Arms