The audience chooses a card from the cards they have shuffled in advance. This card can be signed. Then, the card is placed back into the stack, and just before the stack is placed back into the box, the audience can clearly see that the card they chose is somewhere in the middle of the deck. The magician holds the card box with both hands, and the cards chosen by the audience slowly rise from the middle of the stack.
Effects can be checked before and after the results!!
You can also use borrowed cards for performances!!!