Piatt Envelope trick
" This is one of the most devious and ordinary looking props a magician and mentalist can use! The concept of multiple outs is a powerful weapon when used in a mental or magical effect. Books have been written on the subject and hundreds of props have been invented to produce the desired results. These envelopes are among the best and fairest methods ever invented. The envelopes are standard looking 4.25 x 2.5 inch coin and 5.25 x 3.5 inch invitation envelopes. The handling is direct, there is no fumbling and no extra handling. Just open the flap and dump out the correct prediction. Comes with two specially manufactured and assembled envelopes, photo-illustrated instructions and ideas for many uses. "
Meir Yedid Magic
