A stainless weld-in bung giving a male AN20 flare port, the largest size in this range. AN20 exists for applications where volume is everything and pressure is low: main coolant and header tank connections, large crankcase breather and vent lines, dry sump reservoir feeds and bulk fuel transfer. Stainless is the choice for stainless fabrications and for ports sitting in heat, damp or coastal conditions where long-term corrosion resistance matters. Weld with matching filler and build the weld in well-spaced stages, because a port this large will distort quickly under concentrated heat. The mating AN20 hose end seals on the 37-degree flare, so no thread sealant is required.