The X20 Series Muzzle Brakes combine JMAC's effective RRD muzzle brake design and a direct thread mount for several popular suppressors as well as their BDS-20 Blast Shield! This allows you to leave the muzzle device installed and simply thread the suppressor over! Reduces weight, length, and cost compared to QD systems. Direct thread is also the preferred mounting method for accuracy! Product Specs: 14-1LH Barrel Threads 1.48" long (adds approx 1") 10MM Diameter Bore 1.203-28 External Threads 17-4ph Stainless Black Nitride Timing required for proper function. Compatible with BDS-20 Blast Diversion Shield and DeadAir W Mfg: Jmac Customs