Do take care if you are mad like me, and rehab old 60's era pack and head flash.

I have a Braun Hobby EF-300, that works just fine now that I power it from new gel cells.
On full power output the trigger voltage I measured at 512Vdc.

I have a good quality Wein optical sync that gets used to trigger that thing in a multi -falsh setup.
Even they sometimes fail after living with that rig for a few years.

I put up with it though, because it is a relaible 100w/s on half power, or 200w/s worth of whump when I need to blast light from a softbox, or other diffuse modifier that swallows too much useable output from battery powered flash units with lesser output.