Copag is a famous brand for the cards and the 100% plastic cards are popular for its good quality. Many customers prefer the normal marks in the middle on the back, because the marks are big enough to see and the signs of normal marks are easier to recognize than the special big marks.
As that shows in the picture, the marks have the same signs as that of the four suits of playing cards.
The card on the upper left is SPADE 2.
The card on the upper right is HEART 4.
The card on the lower left is CLUB 6.
And the card on the lower right is DIAMOND 8.