It looks like a set of Dr. Rhine's original ESP cards with simple symbols to test whether it is possible to transfer thoughts between two people.
The symbols are: circle, cross, waves, square and star and you receive a set of 25 cards - 5 of each.
The backing pattern looks simple and impervious, dark blue with little white stars. But in the pattern, in the upper left corner there is a slight mark, so you know which character is on the front, which allows for many interesting effects.
You receive the cards without instruction.