Does this one look familiar...it might...it's a metal shower curtain ring. That's right, before all those stylish new fangled plastic ones, they had metal shower curtain rings. With any of our hang toys, you simply tie a knot around the shower curtain ring and hook the ring on your pet's home to make a wondereful tug style toy. (toy not included). Works great with any of our hanging toys and even on the dumbbells!