invisible ink marked cards

invisible ink marked cards is a kind of playing cards which is more practicle because of using a special contact lenses. When u wear this infrared contact lenses, u can see the marks in the back of the cards.
  The marked cards we produce are the best and most advanced in the wold. They r very useful in the magic show and help u win in the gamble playing card game. We have a variety of invisible ink marked cards, if u r interested in this, go:
http://www.markedcardscontactlenses.com/about-us.shtml