Use a Small End Coupling (male) for connecting pipe to pipe and flexible hose to pipe. 24 gauge construction. Use a Large End Coupling (female) or short piece of spiral pipe for connecting fitting to fitting. 24 gauge construction.
Use a Large End Coupling (female) or short piece of spiral pipe for connecting fitting to fitting. 22 gauge galvanized construction.
Use a Small End Coupling (male) for connecting pipe to pipe and flexible hose to pipe. 22 gauge galvanized construction.