This is a small wooden treasure chest in which, for example, a recently disappeared coin could reappear (or even a ring, as the name suggests).

This is what it might look like: While the coin is still rattling violently in a "rattling box," you reach into your pocket, pull out the ring box, and hand it to a spectator.

Suddenly the rattling stops, and when your helper opens the ring box, the coin is inside.

Or: a ring disappears under a "ring cloth" and is already in the ring box

(Delivery without ring)