The magician announces that he will take his spectators "Behind the Stage" and breal the magician's code and reveal to them how a trick works. He turns around, his back to the audience, and performs the effect for an imaginary audience in front of him. He picks up a thin tray draped on three sides, which represents a stage, and holds this with the undraped side to the real audience telling them that they are "Behind the Stage".
Two thin panels are displayed and inserted upright into grooves attached by blocks to the tray. Picking up a jumbo playing card the magician drops it in between the two panels. It drops clean through the slot in the tray and comes to rest in the loops hanging beneath the tray. This is clearly seen by the audience. Performer now removes the panels, displays them freely to his imaginary audience and takes a bow.
Now the magician faces his real spectators and explains that they have just seen a real mystery from "Behind the Stage". He then suggests that they might like to see it performed in the normal way. The trick is repeated while facing them. This time they are really fooled as the performer really makes the jumbo card vanish into thin air.
There are many versions of this effect on the market. This model is made using "Behind the Stage" to last forever.