I have a pair of Hartenberger 250 TTL HS Digital flashguns for sale that were used with my housed Nikon D700. They are fully Nikon iTTL compatible and support preflash with a suitable strobe adaptor (e.g. Heinrichs & Weikamp). GN 22, 90 degree field of illumination, sub-second recharge and 200 full cycles / charge.
They have been excellent guns used to take pictures such as these here. Unusually, they are depth rated at 100m so well suited to RB/trimix diving.
I regret having to sell all my kit but I have a mastoid problem that may or may not be fixable via surgery that could take a year to arrange 
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You can view them on eBay:
For more info about the guns go to www.hartenberger.de
Thanks, James
