The SilencerCo AC26 Osprey/Octane Piston 13.5M x 1LH 9mm Stainless Steel is engineered for fast, reliable adaptation across firearms by allowing easy piston changes to match different host pistols and calibers, with a 17-4 stainless steel composition that is heat-treated for maximum durability. This piston is a key component of the Nielsen device, enabling smooth movement and reliable semi-automatic cycling to unlock pistol barrels, while offering versatility for fixed-barrel applications when a Fixed Barrel Spacer is installed. Designed with female threading to securely attach to SilencerCo threaded barrels, the XL piston option provides extra length between the threaded barrel and the silencer for configurations that require additional spacing. The 9mm stainless construction and precise M13.5x1 LH thread pattern ensure a robust, repeatable fit across compatible SilencerCo setups, supporting efficient maintenance and quick field swaps. Ideal for shooters who demand modularity, consistent cycling, and dependable performance across varying hosts, calibers, and configurations, this piston system integrates seamlessly into a streamlined workflow for optimizing suppression effectiveness and firearm compatibility in a clean, professional package.