Have you ever heard or used this kind of perspective sunglasses for poker cheat in casino, Texas holdem or other different poker places? Now let us introduce a kind of perspective sunglasses from our company for you. This kind of perspective glasses are specially designed to read the invisible ink marked cards that are printed with invisible markings on their back. We cannot read the markings by naked eyes but if you wear our perspective sunglasses, you will see these markings clearly. Our perspective glasses are the same as common sunglasses in appearance, so it is quite safe for you to use. You also can customize this product for your special requirement.