Magicians Insurance Policy.
The magician has a card selected. He fails to find it. Luckily, for just such emergencies, he has an insurance policy. The policy is opened up by the spectator to discover...a picture of the selected card printed inside the policy that's large enough for everyone in the audience to see. This is an inexpensive way for magicians to carry a "big" trick in their pockets. Popular for years. A proven winner.
Magicians Insurance Policy