Some states do not allow flash suppressors, some only allow muzzle brakes. So there is a distinction to keep the Kalifornians out of jail.
I need it for my Short Barreled Rifle. I have a 7 1/4 inch barrel, and I had the gas port machined a couple thousandths larger to increase the pressure since my dwell is decreased big time, and the KX3 keeps more pressure in the barrel after the projectile passes the gas port.
And it looks bad-ass.