A flash hider is a device attached to the muzzle of a firearm, designed to reduce the visible signature of the gun's flash when it is fired. This helps to conceal the shooter's position, especially in low-light conditions, by minimizing the bright light produced when gunpowder ignites. Flash hiders work by dispersing the gases that exit the barrel, cooling them and reducing their brightness. They are commonly used on military rifles, such as the M16 and AR-15, to enhance stealth during nighttime operations.