A light gun is used to more realistically simulate holding a weapon in a game, this style of controller can be seen in many arcades and has been also created for home versions. Varying incarnations have appeared over the years, the latest being the Wii Zapper. It should be noted that the Wii Zapper is not an actual light gun, but a shell for the Wii Remote, to emulate the feeling of using a light gun.
Controversy arises over the nature of the light gun, many parental groups feel that the Light Gun desensitizes users due to its resemblance to an actual gun.
Light guns, such as the early Zapper for the NES and early light guns in arcades function based on flashes of light. An initial flash of white across the entire screen, followed by a flash of white over the target areas. If the photodiode in the barrel of the gun sees two flashes, it counts it as a hit. If it sees one flash, it is considered a miss. More recent guns in arcades, such as Ghost Squad and The House of The Dead 4 use tracking systems similar to Wii Remotes. This enables additional gameplay elements, such as in Ghost Squad of freeing hostages.