Duel Gazer

A Duel Gazer, known as a D-Gazer (Ｄ－ゲイザ, Di - Geiza) in the Japanese version, is a device in Yu-Gi-Oh! ZEXAL which is worn over a person's eye. It allows the wearer to watch duels in an augmented reality setting.

In anime, they have been shown to be used as communicators, such as phones. They have also been shown to link together two different Duel Gazers for Duels and allow any other Duel Gazers to link to the Duel to see it. This most likely allows spectators to follow just one Duel even if there are multiple Duels using Augmented Reality occurring in the local area.

Like Duel Disks and Duel Runners, Duel Gazers have a standard version (light grey with blue lens), but also has different design colors, and different versions can be adapted with glasses as seen with Flip. Nelson Andrews' Esper Sparrow mask can be connected with a Duel Gazer in a similar way as Flip's glasses.

Duel Gazer Tattoo
A tattooed shaped Gazer characterizes on appearing over a users' left eye which at the same time changes color and a tattoo-like mark appears around that eye.

Kaito Tenjo is the first duelist seen capable of dueling without a normal Duel Gazer. Consequently III, IV, Droite and Gauche are capable of being able to Duel like that as well.

Trivially, all of this individuals might have obtain this ability from Dr. Faker himself. Tracing back on the fact that all of them have a connection to this person.

In addition, although Astral doesn't need a Duel Gazer to Duel, his left eye is golden, as opposed to his light blue right eye, which is similar to the fact that a person wearing a Duel Gazer tattoo over his eye has his left eye color change.

Trivia

 * Although Droite and Gauche have normal Duel Gazers, in episode 37 they are seen dueling with tattoo-like Duel Gazers like the ones used by Tron's family and by Kaito.
 * IV also used a normal mechanical Duel Gazer in the National Duel Circuit, but during the WDC, when dueling Caswell and Bronk, used a tattoo-like Duel Gazer.
 * Cathy wears glasses, but instead of using a special model to be attached on it as Flip, she just removes her glasses and wears a normal mechanical Duel Gazer.