A stainless weld-in bung giving a male AN16 flare port. AN16 is used for high-volume, low-pressure plumbing such as coolant and header tank lines, crankcase breather and vent runs, dry sump reservoir connections and large fuel transfers. Stainless makes sense when the vessel is stainless, or where the port lives somewhere hot, damp or salt-exposed and you want it to remain sound and serviceable well down the line. Weld with matching stainless filler and build the weld up in stages, because a large port concentrates heat and distorts easily. The mating AN16 hose end seals on the 37-degree flare, so no thread sealant and no over-tightening.