|Coronet 66 with "Coro-Flash" unit|
image by John-Henry Collinson (Image rights)
The Coro-Flash was a flashgun with a hyperbolic reflector, manufactured by Coronet. It was compatible with makes of camera other than Coronet, most notably the Conway series by the closely related firm Standard Cameras Ltd.
The Coro-Flash takes bayonet-type single-use flash bulbs like the Photoflux PF3N, PF14N or PF25N. It can also take baseless flash bulbs such as the Photoflux PF1, if a suitable adapter is used. There is a quick release lever on the back so bayonet bulbs can simply drop out without being twisted. However, in the blog post linked below, a standard torch (flashlight) bulb in a bayonet adapter is being used. This is to test that the synchronised flash circuit is working before wasting a frame of film and a flash bulb.
The reflector and backing are made from black plastic and the unit is very light. The silvering of the reflector is simply painted on.
The unit takes two Ever Ready No. U.12 batteries - similar to modern AA batteries - to fire the flash bulb.