High Tech Magic!
The magician has 5 people from the audience select a marble from a bag. Four will select a white marble and one a black one. The magician will always know who selected the black marble. Effect 2: A spectator is asked to place a black marble in either hand behind their back or they can place one black and one white marble in each hand behind their back. They are then asked to bring their closed fists out. The magician can then reveal which hand has the black marble. The "device" is extremely clever and undetectable. You won't believe it yourself. Child's Play III comes with everything you need to perform, including the gimmick, marbles with black velvet bag, and detailed instructions.