Briley Replacement Chokes for Factory Threaded Barrels: these are shotguns, from the factory, that were choked at the factory. These are 99% of Benelli, Beretta, Browning, etc.
Briley Thin Walls for Briley Threaded Barrels: these are shotguns we threaded AFTER they left the factory. They will be a series choke, such as series 1, series 3, etc.