I am trying to find a union for a new radiator I got to replace this old one. the union is permanently connected to the old radiator, so I can't reuse it. it is a male connection into the radiator that is 1.5 in (i assume npt). and a male sheer connection that fits into the supply line but that tightens down with a nut onto threads that are on the supply valve. the threaded part of the supply line is about 2 inches across. I'm finding a lot of unions online, but most don't have a nut with threads inside, just a nut that is fixed onto the union to tighten the union as a whole.