HUXWRX HUB DIRECT THREAD ADAPTER 1/2X28 Made from 17-4 Stainless Steel and is heat treated then black nitride is finished for improved wear and corrosion resistance. This accessory is for use on fixed barrel systems. WARNING NOT FOR USE ON UNLOCKING OR RECIPROCATING BARRELS AS IT MAY CAUSE DAMAGE TO THE SUPPRESSOR Features: Interchangeable with suppressors that have 1.125x28 threads Interchangeable between RAD 9 and 45 Wrench flats