A prediction envelope is on the table and half of a deck is given to the helper and they are told to place the deck behind their back and reverse a card and put in back in the deck as you do the same with the other half. The cards are brought forward and spread on the table. The two face up cards are shown to make a perfect blackjack hand.
The envelope is opened and the two cards inside match the two face up cards.
The cards from the envelope are turned over and they have matching back designs to the deck you are using and when the face up cards that are in the deck are turned over, they have different colored backs!
For an extra kicker, the deck is turned over and they are all BLANK CARDS!