Card sleeves (Japanese: カードプロテクター Kādopurotekutā "Card Protector"; Korean: 카드 실드 Kadeu Sildeu "Card Shield"; also known as Duelist Card Protectors) 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. 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.