Constructed from High-Grade Chrome Moly Hardened Carbon Steel.  Standard 5/8 x 24 UNEF thread fits the vast majority of .308, 300 Blackout and various .30 caliber rifles on the market. Additionally, we have added a 3/4-16 outer thread that allows our brake to be mated with our Re-direct Flash Hiders, in-line solvent filters, the NAPA 4003 in-line fuel filter as well as may common oil filters available on the market.