The Flash Bulb

This is a traditional GE5 flash bulb inserted in the centre of a flash gun reflector. They were in use from the 1920s to the 1970s when the electronic flash, which had been developed during WWII, became more widely used.

Definition: A single-use bulb containing a fine filament, metal wool or metal foil. The bulb's contents burn up in a flash of brilliant light when an electric current is passed through it, illuminating the scene in a brief flash.