The Duel Disk (デュエルディスク) is a special disk that allows two duelists to initiate a duel without the use of the cards. The disk comes in two halves: one blue and one red. These are connected by an energy beam which creates an unbroken field of effect around the entire contraption, effectively allowing for duels to be created in mid-air. At the start of a duel, each player inserts their deck into their respective half of the disk. This deck is separated into three smaller decks and placed on a mechanism called an "individual card tray" to prevent illegal cards from being activated. Each card tray is only able to hold one deck of cards, so a duelist must carefully place their three separate decks into the trays. Each of the three-card trays will then feed the topmost card into an energy slot in the middle of both players' disks. This energy slot is what activates the dueling field. During a duel, the "front" of both disks are placed together and their respective halves are joined together by the beam. This allows for two duels simultaneously, but each player only sees what is in their opponent's disk. A duel will end when one player has lost all of their cards and has nothing left to add to the beam, or when both players are satisfied with their cards. At this point, the beam and disks separate, causing both players to lose any remaining cards on the field. The winner is only determined after both players complete all three of their demise. When a duel ends, the beam will open and detach the disks from each other. The disks will continue to spin for a few seconds before falling to the ground. This is done to show that the duel has ended, but also because without some kind of energy source, it would be impossible for anyone to pick up two disks with one hand. Duels are accomplished in a similar way to a computer's shut down, except that neither player can interfere with the duel using their cards, and the only way to end it is by literal card destruction.