NOTE: on the brass thing with the petcock.
Camping world carries two different models of this
One the "petcock" is identical to a radiator petcock, in fact that is what it is.
The other one has a much larger "Throat" a tube nearly the full half inch (perhaps 3/8) with what looks to be a stainless steel pin through it so you can open and close.
THIS is the one to get.
Home is where I park it!