Hexagonal spanner for Fidelity Research FR 66S tonearm

Thanks, I have been able to remove armboard so space may not be an issue.

Believe mine is like Elliot's, with the 2 flat sides. Am hoping to find the right tool locally.

Here is a photo. Have not been able to remove the black knob (I assume it is supposed to be removable and is part of the B60 VTA adjustment?) Before I take a large wrench to a part of an expensive mechanism that does not belong to me, I ask for further guidance.

Well I guess I also do not know how to import pics. Tried dragging and dropping twice but no luck!!

Thanks, the black knob seemed to have a grub screw but I could not find it or manage to loosen it. Have tried to use the provided small metal rods to loosen by hand but failed. Will try an adjustable wrench soon.

Took it to a friend with a clamp and proper wrench, all good now, thanks for all the positive responses, best wishes, LS

Have a pair of channel lock pliers that are just barely big enough to work but I failed to budge it no matter which direction I tried. Will seek help from local that may have better tools & experience.