Flashbang grenade

A flashbang grenade, also known as a flash grenade or stun grenade, is a special type of grenade used by the UNSC. Unlike the M9 frag grenade, these grenades are not intended for lethal use.

Overview
Flashbangs use chemical reactions to produce an extremely bright flash of light and a very loud concussion blast when deployed, stunning targets, but doing very little physical damage to them. The primary purpose of a stun grenade is to temporarily blind and deafen the enemy. If the victim directly observes the flash, a still frame of what is observed by the victim will be seen for up to ten seconds, at which point their eyes will have returned to their unstimulated state. The flashbang grenade's use in combat scenarios has not been overlooked, serving to confuse, disorient, or momentarily distract a potential threat for five to ten seconds.

Flashbangs saw widespread usage within 21st century armed forces, and they have been used by the UNSC Defense Force. They were used by the UNSC Marines Hellbringers squad in 2531, during the Harvest Campaign. Orbital Drop Shock Troopers are often equipped with flashbangs. Flashbangs were used during the Raid on Camp New Hope and during the training of the SPARTAN-III Gamma Company.

Trivia

 * Halo 3 possesses a piece of Covenant equipment serving a similar function as a Flashbang, the Flare, which is used to blind all nearby players (even if they can't see it), though it lacks the deafening effect of a flashbang. It does, however, have a noise that can drown out certain other sounds.
 * Starting with Halo 3: ODST and carrying over to Halo: Reach, ODSTs can be seen carrying flashbangs on their belts along with a similar container colored blue with an unknown purpose.

List of appearances

 * Halo: The Fall of Reach
 * Halo Graphic Novel
 * Halo: Ghosts of Onyx
 * Halo Wars
 * Halo 3: ODST