Grey Ghost Precision Muzzle Brake .30 Cal 5/8x24 Thread Nitride Finish Black. Features a unique porting system to redirect the forward moving gasses rearward to greatly reduce recoil. Black nitride coating for durability and ease of cleaning. Easy installation with supplied crush washer. Specifications for Grey Ghost Precision 30 Cal Muzzle Brake: Manufacturer: Grey Ghost Precision Color: Black Projectile Caliber: .30 Caliber Finish: Black Nitride Fabric/Material: 17-4 Stainless Steel Stainless Steel Threads per Inch: 5/8x24 Weight: 3.2 oz Included Accessories: Crush Washer Included Package Contents: Grey Ghost Precision 30 Cal Muzzle Brake Grey Ghost Precision GGP-MB-30: Muzzle Brake .30 Cal 5/8x24 Thread Nitride Finish Black