Smoothbore 18-1/2" barrels quickly convert a Remington 870 or Benelli Nova/SuperNova into a fast-handling slug gun or home defense shotgun. Features chrome-lined bore and Carlson cylinder-bore choke tube installed. Remington 870 barrels are threaded for standard Rem Choke and have 3" chambers. Does not fit 870 Tactical models. #155-000-252 has fixed Cylinder choke. #155-000-253 has rifled bore. Benelli barrels have 3-1/2" chambers and are threaded for Benelli Mobil choke. Both are available with a choice of ramped blade front sight only or adjustable front/rear rifle sights.