Not sure what you mean - are you trying to string two arms together to make them longer? If so, I wouldn't advise it, because this arm isn't rigid enough to support such an endeavor. Out of the water, this thing already flops over from my big (Sea&Sea YS-120) strobes; in the water, it's OK but if there were a strong current, these would probably flop back, to say nothing of making them even longer. I suggest you get thin straight-arms with joints if you want longer spread for your strobes.
Roy L I would like to attach this to the Ikelite Stem Mount with Ball for Flex Arm with a 1.1 inch ball. This would let this arm attatch to the Ikelite handle and have the universal type mound at the top.