The magician asks the spectator to select a card and make some shuffle.
Then, he shows the chain with his neck to the spectators, ensuring it's normal.
The magician put the deck near to the chain, and count:3,2,1. wow...unbelievable!!!! The chain through the card which is the selected card. And then hand it over to the spectator to check. it's really through the card
See the DEMO and you will know how amazing it is.
Demo: