It's like tubing with a slit that you force open somehow to get it on the ring. Mine fell off my ring the first day I wore it and got lost. The bigger tubing for the bigger ring m-i-g-h-t stay on better. It has 2 small, 2 medium, 2 large. Well, what if I want 6 small. Too bad. Three times the cost for something that won't stay on. It is more comfortable than the metal one I also bought. There doesn't seem to be a good one to buy which stinks because fingers get bigger or smaller and need adjustment. I recommend consulting a jeweler although I haven't yet. Someone needs to build a better "mousetrap" so to speak. Oh, yeah, and they are sooooo stingy for cheap tubing with a slit in it. If they had given me a dozen of these things, I would have given them a better rating. I feel cheated.