Tell O'Clock prediction by Mr. Magic - Trick

A small box with sliding door is introduced. When the lid is slid down the face of a clock is seen inside. Spectator is asked to mentally select any hour between 1 and 12. After the selection has been made the spectator is instructed to rotate the hand to show the selected time and close the cover of the clock. This is done while the performers back is turned (the performer can actually be out of the room)! The performer turns around and immediately announces the exact time the clock was set to. The performer never even touches the clock! This magic trick is astounding and is very easy to perform!