Yu-Gi-Oh! Duel Monsters - Duel Disks

DiaDhank Duel Disk
Based upon on an ancient Egyptian artifact called a "DiaDhank", a golden device worn similarly to the Duel Disk that uses the user's Ba (Life Force) to summon Ka (spirit monsters) from their stone tablets and control them. Unlike the Duel Disk, the DiaDhank can only control up to 3 monsters at once. In place of the Life Point counter is the Eye of Wdjat, which contains a glowing yellow meter that measures the user's Ba, as the disk measures life points. In the Egyptian times, the cards where called stones.

Duelist Kingdom Promo Duel Disk
During the Duelist Kingdom arc, Seto Kaiba developed the first generation Duel Disk prototypes as a means of countering Maximillion Pegasus' mind reading abilities. The wrist component stores the Deck, Life Point counter and the actual disk component holds five cards. Users would load the cards as explained later into the disk and throw it like a yo-yo, causing a hologram to be projected from it.

Battle City Duel Disk

Unlike the previous Duel Disk, it did not need to be thrown. When it first appeared in the anime, sealers flew out of the Duel Disk to the sides of the Dueling area to produce the Solid Vision holograms. These were removed later. In the manga the holograms were projected straight from the Duel Disk itself. Directly underneath each monster slot is another slot for Spell and Trap Cards. If a Duelist was to activate a Set card, they would activate a button on the round portion of the disk. Another slot can open on the front end of the disk that is used for the Field Spell Card. The center of the disk includes the Main Deck and Graveyard slot and Life Point counter. The bottom part of the Disk, which goes around the user's arm, also contains a retractable cable that could be attached to Dueling Arenas if one player opted not to use a Duel Disk.

Chaos Duel Disk

The Chaos Duel Disk is a Duel Disk designed for the members of the organization called Doma in the Waking the Dragons arc. Functionally, it is identical to the Battle City Duel Disks, other than the fact that the field area of the standard version can retract and expand as opposed to being split in half, while the Orichalcos Soldier version is built into their arm-mounted weapons.