Breek Arms Plan B System Echo Single Port Brake 9mm 1/2x28 Black. Ultra-compact single-port design for the Plan B mounting system. The Breek Arms Plan B Echo Single-Port Muzzle Brake significantly reduces recoil and muzzle rise through 90 horizontal blast-vectoring ports keeping your rifle flat fast and ready for seamless suppressor swaps. Specifications for Breek Arms Plan B System Echo Single Port Brake: Manufacturer: Breek Arms Color: Black Caliber: 9mm Luger Package Contents: Breek Arms Plan B System Echo Single Port Brake Peel Washer Breek Arms BRK4433: Plan B System Echo Single Port Brake 9mm 1/2x28 Black