Earpiece

The Earpiece is a piece of gear featured in the HD Universe of the Grand Theft Auto series.

The Ballad of Gay Tony
Luis uses an earpiece only during the Club Management side mission, where he receives instructions from Joni for basic management or from Dessie for important tasks for VIPs and celebrities.

Grand Theft Auto V
The Earpiece is presumably a Bluetooth earpiece connected to the player's phone. It is used by protagonists to communicate with one another during heist missions. It is a cosmetic item with no practical usefulness over the default earpiece provided in the heists.

Grand Theft Auto Online
The Earpiece was introduced as a purchasable item in Grand Theft Auto Online as part of the Heists Update. There are three variations: a basic gray one, a red one with a different shape and an LCD one.

When the player talks when using a mic and the earpiece on, a blue light will flash on the side of the earpiece.

Grand Theft Auto V

 * The earpiece is automatically worn by protagonists during heist setup missions and heists. It is also worn during various missions to allow the protagonists to communicate. It is an integral part of the Scuba Gear outfit, though it can only be seen by removing the top part of the outfit through a glitch.

Grand Theft Auto Online
The three ear pieces are in the heist gear section of Ammu-Nation. All three models are available by default.
 * Gray Earpiece: $1,200
 * Red Earpiece: $1,350
 * LCD Earpiece: $1,500

Trivia

 * The LCD Earpiece appears to be the same as in No. 3, from The Ballad of Gay Tony.