Marked deck of cards

We also call marked playing cards as marked deck of cards. They are marked deck trick but infrared ink glasses can see through playing cards. Marked card and invisible ink contact lenses are good for magic show.
Invisible ink for playing cards are well-hidden enough so that we need to get the help of infrared contact lenses. You can see marked cards clearly when you using infrared contacts. But naked eyes cannot find marked deck trick. Why not buy marked playing cards with great quality from us?