Pen mark is an original and simple way to mark cards. The invisible ink pen is a necessary tool to mark invisible ink cards. The marks written on the back of cards can not be seen with the naked eyes, only special for the IR sunglasses or contact lenses.
 
Either the paper cards or the plastic cards can be marked by the invisible ink pen. One pen can mark more than 50 decks of cards.


The invisible ink pen is very convenient to mark cards in many poker occasions like home games, club games or casino games.