AAC MUZZLE BRAKE MK-SD 7.62MM 90T. 62MM 90T - The AAC BlackOut Muzzle Brake 90T 7.62MM. This highly effective muzzle brake is compatible with the AAC Mk13-SD 90T sound suppressor. All AAC Blackout muzzle brakes are machined from high strength aerospace steel alloy and coated in a hard durable corrosion resistant SCARmor finish. Specifications for AAC 65017 MUZZLE BRAKE MK-SD 7.62MM 90T: Manufacturer: Advanced Armament Corporation Finish: SCARmor Fabric/Material: Steel AAC 65017 MUZZLE BRAKE MK-SD 7.62MM 90T