Universal Mercury II 05

The UniVex  Mercury Flash Unit slips onto the "hot shoe" in front of the shutter housing and uses large screw-base flash bulbs and two AA batteries. Lots of light is needed for the slow films of the day. My camera has an adapter so that 25B bulbs can be used. Some owners have converted Canon electronic flash units so that they can be used. Blue bulbs are for color, clear ones for b&w.
The shoe on the right side next to the rewind knob was for an optional exposure meter.