Midwest Industries AR-15 9mm/9x19 Two Chamber Muzzle Brake Black. Large two chamber design reduces muzzle climb for better target acquisition. Specifications for Midwest Industries AR-15 9mm 1/2x28 Two Chamber Muzzle Brake: Manufacturer: Midwest Industries Color: Black Projectile Caliber: .355 Caliber Finish: Phosphate Threads per Inch: 1/2x28 Gun Make: AR Platform Gun Model: AR-15 Condition: New Country of Origin: USA Gun Type: Rifle Features of Midwest Industries AR-15 9mm 1/2x28 Two Chamber Muzzle Brake Large two chamber design reduces muzzle climb Constructed from tool steel with a phosphate finish 1/2-28 threads for 9mm/9x19 rifles .410" diameter hole Includes new crush washer Package Contents: Midwest Industries AR-15 9mm 1/2x28 Two Chamber Muzzle Brake What firearm models does the manufacturer say Midwest Industries AR-15 9mm 1/2x28 Two Chamber Muzzle Brake is compatible with? The manufacturer suggests that Midwest Industries AR-15 9mm 1/2x28 Two Chamber Muzzle Brake is compatible with AR-15Midwest Industries MI-MB9: AR-15 9mm/9x19 Two Chamber Muzzle Brake Black