I had a brass reducer fitting break on my hose reel today. The way it broke left just the threads in the reel. Grabbed my handy internal pipe wrench and backed her right out. Just thought I would share for those that have never used one. oh, and I replaced it with a steel fitting.
There are different sizes, that one is a 1/2 inch. There is a piece of metal that moves outward as it turns which puts more pressure the more you turn it.