The magician says the cards know which one is missing from the deck, and they will tell everyone. The only thing the magician must do is snap his fingers to make them "speak". He proceed to snap his fingers and spread the cards to show a card magically appearing face down in the middle.
When the magician wants, they all appear to be in matching couples (e.g. Jack of hearts and Jack of diamonds). The rest of the deck can be shuffled by a spectator and the same thing will happen with every single couple (e.g. 10 of clubs and ten of spades, etc, etc).
A spectator shuffles a deck of cards and another spectator simply names any of the four suits. The magician retrieves the pack and then quickly cuts it into 10 piles. Amazingly, the first packet is counted and found to contain just one card! The second packet contains two cards, the third three cards and so on, all the way through to the last packet containing exactly 10 cards!
These cards are built with the best material and the marking system is clearly visible to the performer but completely invisible to the audience. With this deck you have a powerful marked and ordered deck that allows you to perform clear and shocking miracles.