Add-A-No type effect that is completely safe and easy to use.
The Zimmerman Dangle Book is one of the best forcing utility props available today. Simple but very effective. Can be used in a number of ways, but the most often used effect is the prediction of the total of a series of numbers generated by your audience.
The numbers are jotted down and added and the total ALWAYS matches your prediction. Total can be different every time.
Fits in your coat pocket, always ready to use. Spiral notebook style. Black.