Rugged Suppressors Fixed Mount M18x1 Black. 375 X 24 thread pattern to mount directly to the barrel of a firearm. The Universal Direct Thread Mount is available in 5 thread pitches and enables the shooter to quickly install a universally threaded suppressor to their firearm. Specifications for Rugged Suppressors Fixed Mount: Manufacturer: Rugged Suppressors Additional Features: Mount Fixed Mount Package Contents: Rugged Suppressors Fixed Mount