I just saw a NEMA head that had a red "17" sticker on it. It didn't look that old, possibly installed within the last few years. I don't have any pics unfortunately, but are metal halide NEMA heads rare?

I have heard of MH NEMA heads, and idk if they're rare. Did this have a closed bottom lens?

I have heard of MH NEMA heads, and idk if they're rare. Did this have a closed bottom lens?

There was a bulb sticking out a little bit out of the bottom, so it was probably open bucket.

Ah, must have a protected arctube bulb then. The unprotected bulb bases have a flare and are slightly shallower than the protected base bulbs so they can't be used in an open, exposed fixture.

Ah, must have a protected arctube bulb then. The unprotected bulb bases have a flare and are slightly shallower than the protected base bulbs so they can't be used in an open, exposed fixture.

That makes sense as to why the lamp stuck out a tiny bit.