This is a fitting

Teemok

Is it a rogue, counter culture, problem, uncouth fitting. Nope, it's just a fitting.
It's made for one thing and some may recognize it. It fits into a water heater heating element hole and converts it to FIP. Not an easy find. Is it a discouraged fitting? Maybe it is. It allows for connections that some desk sitters don't want made. If you didn't know, now you know. What you can do with it is up to you. You can figure out the sizes. I've not had one fail or leak. The first run in is tight. Anti seize or just T paste. SS is what I have but brass would work.
One of my hero's is Robert De Niro's character in the 80's movie "Brazil" The great Harry Tuttle. This post is in his honor. Central Service guys, don't waste your time. In keeping with Tuttle's style, comments will not be responded to. News papers swirl up into the air and he's gone.

GroundUp

I've been using those to adapt BSP to NPT for 15 years now. Typically on a radiant manifold. But now you've given me a good idea to use some leftover manifold valve/union/thermometer tailpieces on my next water heater buffer tank application.

hot_rod

Is it plated? Maybe for a radiator valve adapter.

Alan (California Radiant) Forbes

I don't like yellow. Does it come in other colors?