Would this work for a shower arm peace that has broken off in side the wall that is in the threaded 90 that it conects too

It is designed to work with pvc pipe .counter clock wise rotation digging into the pipe to unthread it. As long as the shower arm , brass,steel,copper or pvc pipe isn't tighten to tight it should dig In enough to loosen the broken piece before rounding off the flutes of the tool as they are made of softer metal. At $4.50 if it works once ,then throw it away it's cheaper the tearing the shower wall apart . Hope this helps Other wise go to the hardware get an easy out for steel

curtis, this extractor is designed for use with risers that have been installed as part of an outdoor irrigation system.