Yankee Hill Machine Co Mini QD Muzzle Brake, 9MM, 1/2-28, Black, Includes Shim Kit YHM-3109-1MB-28A Introducing the highly anticipated Mini QD Brake with a 9MM Bore for YHM's fast attach sound suppressor systems. The Mini QD Brake is YHM engineering perfection. Compact at only 1.6 inches and weighing in 3.2oz the Mini QD brake was designed for today's competitive shooter. No short cuts were taken" and users will find that the Mini QD brake is still capable of being shot comfortably unsuppressed as well as suppressed. Currently Available in 5/8" - 24 and 1/2" - 28 thread pitches. Upgrade your favorite firearms today with a Mini QD Brake.