The Tooth Shield Tackle Brass Ball Bearing Swivel w/ Double Welded Rings is an incredibly strong ball bearing swivel used in freshwater and saltwater applications. The swivel is constructed of a super strong marine grade brass and utilizes dual welded rings extending from each side for connection points between lines. These swivels will be the smoothest ball bearing swivel you'll have ever used. Why are these ball bearing swivels so special? It's the dual rotation engineering that allows each side of the swivel to spin independently in a single body piece design. This is the primary factor behind the bearings unparalleled strength to size ratio.