Show your spectators the white string that is hanging outside one end of the colored plastic box. You slowly pull the string through the box and it is seen to magically change into a red string!
If you wish you can start by showing the red string and cause it to change into a white string. Very easy to do! Self-working!
Vintage New Old Stock. Supplied inside a poly-bag with header. Comes in a choice of three colored boxes: Red, Green, or Blue. Please specify your color choice when ordering. Color choices available while supplies last.