JARD Twisted Ported Brake .450 Bushmaster 2in Length 11/16x24 4140 Steel Alloy Black. This brake disperses the majority of exiting gas radially reducing backward force and felt recoil. Comparatively traditional barrels or barrels without muzzle devices gas is predominately expelled linearly creating backward force that adds to recoil. Specifications for JARD Twisted Ported Brake: Manufacturer: JARD Color: Black Projectile Caliber: .450 Caliber Caliber: .450 Bushmaster Fabric/Material: 4140 Alloy Steel Threads per Inch: 11/16x24 Outer Diameter: 0.75 in Length: 2 in Package Contents: JARD Twisted Ported Brake JARD 4209: Twisted Ported Brake .450 Bushmaster 2in Length 11/16x24 4140 Steel Alloy Black