Have someone pick a card in a shuffled deck of 52 cards, ask him to put it back in the pack. Put on the Spex glasses and give him a lighter, once the flame flights up, you're able to reveal the card!
Perhaps, your spectators would like to see this experiment once more, ask a second spectator to select a different card, give the glasses to your first spectator and as you light the flame, he is not going to belive what he sees.
 
• An easy effect that your audience will be sure to remeber!
• Only the special glasse are suplied. The deck and lighter are not supplied. You can use your own or even borrow them