The Flash-Bang Grenade or Stun grenade is a special type of grenade used by the UNSC. Unlike Fragmentation Grenades, these grenades are not necessarily lethal. They pack explosive force and shrapnel, but they are more designed to stun a target instead of killing it immediately.
There are a variety of uses for these. They have been used in military exercises by the UNSC, at least since 2525. They are also occasionally used in combat as well, serving to confuse, disorient, or momentarily distract a potential threat for to five to ten seconds. Although a flash-bang can seriously degrade the combat effectiveness of affected personnel for up to a minute, they are still vital in any hit-and-run operation.