These are dual index cards, meaning that there are two different sizes of indices - there is a smaller index in each corner of the card as well as a larger index in the center of the card. The smaller, corner indexes allow players to flip up the corner of their down cards (hole cards) to view them - this exposes as little of the card as possible, ensuring that other players cannot see your hole cards. The corner indexes are rotated in a slightly counter-clockwise position since most players peek at their hole cards with the cards held at an angle. The larger index in the center of the card is helpful when viewing the board cards (cards face up in the center of the table) from a distance.