A friend of mine has bought such a coupling ring. After we had hours tossed him I knew: as a union ring I will have. It is available in two sizes. This is the smaller version. The ring flies usually wider than normal Frisbees. It's hellishly fun to throw him over a football field. It flies extremely accurate. He departs again from the direction from one can bend it a little and you're back straight. All in all, it makes great fun - a 'must have' for all Frisbee fans (and those who want to be)!