Contact lenses for back marked poker, is invisible. When you wear it, just like wear nearsightedness contact lenses, others could not know you wear something. And we do the mark on the back of poker by special ink, without the contact lenses, you can see nothing, while you are wearing the lenses, you can see the mark clearly.
   In order to see the marks clearly, we suggest you that use the under the fluorescent lamp. If you want to use it under the sunshine, please tell us advance, cause the poker should be processed specially.

   This device is widely used for private poker party, party gamble, casino, poker match, magic show.