Beretta Threaded Barrel has a threaded muzzle to enable mounting of a compensator or suppressor, it comes complete with thread protector. These are true drop-in barrels with finished chambers and do not generally require any gunsmithing. In rare cases, the fitment may be required. In that case, please see your local gunsmith for proper installation. Features: Caliber: 9 mm1/2x28 thread pitchLength: 5" (127mm)Internal Finishing: ChromedExternal Finishing: Steel, matte Beretta APX 9mm 5" 1/2x28 Black Barrel Assembly JBAPX9TH