Unfortunately, this is not the correct card. Then, you take a silk or a napkin, and wipe the window clean. Amazingly, the card will instantly transform into the spectators signed card, and they then can retrieve the card themselves. All the action happens on the back of the window. Everything can be given for examination! And the spectator can keep the card as a souvenir!

Nearly self working and very easy to perform
You end totally clean
The spectator can get the card themselves from the other side of the window
No force of any kind, the card is freely chosen
Resets in seconds
Self contained, no need of the help of an assistant
Contains all props to perform the effect, except a regular deck of cards and a Sharpie to sign the card