A set of three knurled threaded rings in a bright silver metal finish, in three sizes, each with internal threads and small radial holes through the knurled band. These connector parts are precision components engineered to link systems, compatible with small, medium and manifold assemblies. The straight knurling gives a firm hand grip for tightening, and each ring carries a smooth band above or below the knurled section. The rings are manufactured to meet exact tolerances and material specifications for reliable performance.