If you have been looking to utilize your favorite suppressor on a fixed barrel firearm this is the factory SilencerCo part for you. This mount replaces the piston spring and retainer on your Octane or Omega suppressors turning them into a direct thread mount for fixed barrel firearms. It allows the use of the Octane 9 and Octane 45 as well of the Omega 9K on a fixed barrel firearm with thread size Metric 13.5x1 Left Hand. This piece is made from stainless steel and features a black oxide finish. Specifications and Features: SilencerCo Octane Fixed Mount AC1526 Metric 13.5x1 Left Hand Thread Pitch (SIG Sauer MPX) Replaces your Piston Spring and Retainer on your suppressor Turns your suppressor into a direct mount system for fixed barrel firearms Stainless Steel Black Oxide Finish Fits: Silencer Co Octane 9 Octane 45 and Omega 9K