A flash grenade, also known as a flash bomb was a type of non-lethal grenade which, when activated, created a bright energy flash and loud noise to disorient opponents. It also gave a mild impact although it was not as destructive as thermal detonators, and was capable of disabling droids for a short period of time. One variant of the grenade could split into several fragments and individually explode.
In 14 BBY, the Jedi Knight Cal Kestis infiltrated the Fortress Inquisitorius on Nur in an attempt to retrieve a holocron that contained a list of Force-sensitive children. During the mission, Kestis was confronted by the Inquisitor known as the Second Sister who attempted to use flash grenades to disorientate her opponent during their duel.
When Luke Skywalker went on a mission to Ben Kenobi's home with R2-D2, Boba Fett ambushed them with a flash grenade in an attempt to capture the boy.
- Star Wars: Smuggler's Guide