A
stun grenade, also known as a
flash grenade or
flashbang, is a
non-lethal explosive device used to temporarily disorient an enemy's senses. It is designed to produce a blinding flash of light and intensely loud noise "bang" of greater than 170
decibels (dB)[SUP]
[1][/SUP] without causing permanent injury. It was first developed by the
British Army's SAS in the 1960s.[SUP]
[2][/SUP]
The flash produced momentarily activates all
photoreceptor cells in the
eye, making vision impossible for approximately five seconds, until the eye restores itself to its normal, unstimulated state. The loud blast is meant to cause temporary loss of hearing, and also disturbs the
fluid in the ear, causing loss of balance.
The concussive blast of the detonation can still injure, and the heat created can ignite flammable materials such as fuel. The fires that occurred during the
Iranian Embassy siege in London were caused by stun grenades.