You can find the Dead Air Armament Micro Brake .38 5/8x24 here. Fast $9.95 shipping! Orders over $200 ship for free!

The Dead Air Armament Micro Brake is a lightweight and short single port muzzle brake suited for a variety of platforms. Designed to be used with the KeyMicro Adapter to provide your Ghost, Wolf, or Wolfman suppressor a quick attach functionality similar to the KeyMo system. The Micro Brake is also compatible with the KeyMo system.

Bore: .38
Length: 2.06"
Threads: 5/8x24