The answer is Rigid-metal
Rigid metal conduit is heavy-duty galvanized steel tubing that is typically used outdoors to provide protection from damage. It provides structural support for electrical panels, cables, and mast. Another important advantage of zinc- based rigid metal conduit is that it has no temperature limitations. IMC and EMC are lighter-weight versions of rigid metal conduits and can be bent easily using conduit benders. These two metals are not the best for mast installations.
