Having moved to the Subal V3 TTL board, I'm selling the V2 board that I have used with my Nikon D500 system.
I've used the board with Inon Z240 strobes via fibre optic. The TTL results have been excellent. You can turn the TTL feature on and off underwater easily. The board will work with various other strobes including Sea&Sea YS-D1, D2, YS-250; Inon Z240, D2000, S2000 and Ikelites DS161 and DS61.
The board can be used with either fibre optic connectors or electrical - both obtainable separately.
If you have a Nikon camera with no built-in strobe, eg the D500, D5 or D850, this board will initiate the strobes for you.
Price is £195 + postage
For more info PM me