Thought I would show you my 'Braun Hobby' unit from the late 1950's-'60's that I use to take many of my ;Indoor Photos' . They came out in the 1950's and were used by all the newspaper photographers -- when you see the Beatles coming down the steps of the Aircraft in USA there are all the news snappers with their ROLLEIS and the black Braun Hobby units with the strap over their shoulders ! My FIRST Braun was bought in the Canadian Maple Leaf Store in Iserlohn, Germany in 1957 when I was there in the British Military Hospital as a Path Lab Technician-- it cost � 14-00 when in England with all the taxes it cost � 39-00 ! It had 'lead-acid ' wet-cell accumulators and could also be run off the mains .. I wore out the cells then they were all discontinued BUT I could still run it off the mains indoors. Then many years later I got a second flash head , then I was GIVEN some more Braun units and saved some from being DUMPED by a Photographer I was visiting. There are differences in all the power packs I have when they are opened up -- small improvements by the Germans. The flash duration is 1/1000th second and when more than one head is plugged in of course the power is shared.