An extended-body weld-in bung that gives you a male AN6 port. The extra reach is the whole point: it lets the threaded end stand proud of a thick tank wall, a recessed panel or a boxed section, so you can actually fit a spanner on the hose end instead of grinding away at surrounding metal. Standing the flare seat further from the weld also helps keep that sealing surface from distorting under welding heat. AN6 is the standard-duty size for fuel feed and return, oil lines and power steering return. Weld all the way around, keep heat input controlled, and check the seat is clean before assembly.