RogerT wrote:
....

Here's a new twist. It just dawned on me that I could check another
property that I own and see what the gas line looks like coming in. It
turns out that it also has the same type of silver fitting. Here are
photos of that one:

http://i54.tinypic.com/2nq8lyb.jpg
....

That looks like it could be the dielectric fitting as somebody else
mentioned earlier -- the whole thing instead of having just used the one
end as a bushing as appears to have been done in the other case.

What's the dark section the el is screwed into on this one?

I suppose it is still possible it could be a TCV (thermal check valve)
but the only ones of that size I'm familiar with look similar to this
one from Dresser...

http://www.dresser.com/index.cfm/go/product-detail/product/TCV-Thermal-Check-Valve/

Couldn't find the requirements from PSE&G on their website other than
did find a reqm't for inline check valves on jeweler's NG/oxy- torches
and the like, but they are a much smaller device, of course.

Don't guess there are any manufacturer marks, of course???

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