Mike and Al,
Yes, that little tiny "weatherhead" does go on the end of BX and the loose ends of the wire will then get soldered to the knob and tube. If it was called "Monkey fist" "Bird's eye" or what ever, I am not sure. Maybe Joe T. can answer that. I have never installed it, I have only removed a lot of it while doing rewiring of the old homes here in my area. Also that black tube is called Loom and what the contractors would do, is use this to sleeve the RH wire that enters boxes. The loom would protect the RH when it would have to make a turn into a box, or sometimes when the wire turns the corner.
Caper
