Here is what I got back from Kessil:
"Hello Steven -
Our standard K-link cable is 10' ft in length, you can add an extra 10' ft of length to our cables with the K-link extension cable that we offer.
You can daisy chain up to 32 lights with our K-link cables.
So if you had a light positioned on the far end of the 12' ft aquarium - the 5' ft aquarium would have to be close enough for the 10ft K-link cable to reach over and attach to the light.
If it is not close enough then this scenario may call for the extension cable.
This holds true for power extension cables as well.
Hopefully this information helps! Let me know if you have any other questions
Best Regards,
Arturo"
I made them and I promptly gave them to a buddy to use and he is very happy. I will have to make more when my fish room is done.