From Dave Powell:
The performer places a wine glass on the table and borrows a finger ring from any spectator. The ring is placed in the folds of a handkerchief and given to the spectator to hold over the mouth of the wine glass. He can actually feel the ring through the handkerchief The performer presents a small locked wooden box and sets it in full view of the audience. The spectator is asked to drop the ring into the glass. The spectator lets go of the ring and it is apparently heard as it clinks into the glass. The performer immediately whisks away the handkerchief from the glass and it has vanished! The spectator is then handed a key, and opens the box himself. Rice overflows from the box as it is opened, as he pours the rice out he discovers his ring inside! The beautifully hand-crafted walnut box (approximately 2 ¼ inches square) with inlay hides the secret even upon close inspection from magicians.