These are a great comedy gag, used by Dave Bonsall in his ring routine. It’s so common when you perform a trick with somebody’s ring, to hear them say “…but can you make the diamond bigger” or something similar. All you do is to have a Jumbo Ring ready in your hand at the end of the routine and when they ask, you simply wave your hand and they’re ring is now huge! …it never fails to get a good laugh, see the video for a demonstration.
Please note - Size of the diamond and ring may vary by a couple of milimeters.