Card sleeve

Card sleeves are protective plastic covers used to prevent cards from getting bent or scratched. Most card sleeves are made by third-party manufacturers, though Konami distributes a few styles of their own sleeves.

If a player uses card sleeves, they must all be the same so their cards aren't marked.

In the OCG, it is possible for a player's Deck to contain cards with different backings. In cases like this, it is mandatory for the player to use sleeves to prevent their cards from being marked.

In the video game Yu-Gi-Oh! 5D's World Championship 2011: Over the Nexus, card sleeves can be unlocked and used by the player.