A nice early example of the Dial X effect. This one by UF Grant is built into a small plastic box with a lid.
A plexiglas clock dial is shown, and the mental magi turns his back as the spectator turns the hand/pointer to any number, shows the number to the rest of the audience, and then turns the hand back to twelve o'clock. Turning back to the audience, the mentalist picks up the dial, and asks the spectator to just THINK "yes" or "no" as the dial's hand is moved to each number in turn. The mentalist concentrates, and correctly identifies the thought of number. Can be repeated.
The picture shows that this item is in very good condition, despite being 50+ years old. The box lid has a few cloudy spots on it, but is not cracked. It does not effect the working of the trick.
Instruction sheet is the original Grant instructions.