The REARDEN MFG Alpha Atlas provides a mount interface for suppressors with inside diameter threading of 1.125-28, like the Rugged Obsidian 9 and Obsidian 45. REARDEN MFG does not recommend this on suppressors that use the low profile style adapters, like the Omega 9k. FeaturesLength Added: 0.350"Threads: 1.125-28 (Silencerco Alpha thread pitch)Compatible with short Rearden devices (FHD, Mini, SPB, RPB, R2S)Compatible with Q Cherry Bomb and Other Plan B Compatible Muzzle Devices