Ideal for screwing short barrel nipples into malleable iron pipe fittings, e.g. central heating radiator connections...
I didn't know if it was safe to respond to a thread that was referring to twisted nipple whatevers. I once worked with a nasty girl that would laugh and giggle whenever we used certain words. It wasn't cute, either. She was scary. We renamed parts - nipples were now "short pipes with threads on the end" we just stopped saying dog robbers altogether. I don't know why she had such a cow about those.
We use a nipple wrench, these aren't a nipple wrench in our vernacular- they are internal pipe wrenches and it is okay to laugh at someone using one. The user would probably be an electrician, anyway. A true nipple wrench has short (2-3) threads made onto a sort of through coupling, the end of the pipe is up against a stop and wedged in. When the nipple is made up tight, the stop us released from the nipple end. That loosens everything up and the wrench is backed off the 2-3 threads.
Our smallest steel pipe in fire sprinklers is 1". If I have to back one out above a ceiling I have an easy out welded to 1" pipe. Just stick it up in the pipe and wrench it out backwards.
Chilly