This ring is designed to make it easy to hang a houseplant in a pot with a top diameter of more than 6 1/4" or 160mm. Pots smaller than that will fall through. I originally intended this to use parachute cord, but any string that fits through the holes will do, I'm sure. Edit 12/18/2017: Needed another one of these for 4" plant pots, so I added a 100mm version. Beginning to think of stacking three of these on one set of cords, so another is probably on the way. Might be bigger, might be smaller. Haven't decided yet.