The extended-body aluminium AN16 weld bung. The longer body is there for awkward installations: thick tank walls, recessed or double-skinned alloy panels, and pockets where a standard bung would sit too deep for a spanner to reach the mating hose end. On a port this large that access issue is real, because AN16 hose ends need a substantial spanner. The added length also keeps the 37-degree flare seat clear of the weld pool, which helps prevent heat distorting the sealing face. AN16 suits coolant plumbing, breather and vent lines, dry sump reservoir connections and large transfer runs. TIG weld into aluminium fabrications only, in staged passes.