Bicycle cards are a common prop used by many a card magician in their act. This includes replacement and switch tricks. Some of these call for blank cards to be inserted into a standard or marked deck of playing cards. Many of these effects also need to be able to stand up to cursory inspection from skeptical spectators to help maintain the audience’s suspension of disbelief.
In a moment like this, you want the inserted or replaced blank card to blend seamlessly with the rest of the deck. Even the slightest of deviations can become astoundingly obvious to a small crowd or street performance close up act.
These double blank cards are just like standard Bicycle Blue cards. They have the same rounded corners and finish to blend seamlessly into your standard, force, or marked deck of Bicycle playing cards. With proper practice you can then swap them in and out of the effect with little more than some deft sleight of hand.