Now you can secretly write a message, number or symbol on a whiteboard. Thanks to this gimmick you will be able to write with a chalk on a blackboard and be able to make predictions on what you previously stated.
Real standard chalkboard is used. Easy to use, the plaster will appear with a simple gesture.
Usable for both right and left handed. With a simple gesture, the chalk will disappear.
Standard size by Vernet. Attach video instructions.