A steel weld-in bung that adds a male AN4 port to any steel fabrication. Because AN4 is a small-bore size, it is the one to reach for on gauge and sender lines, boost or vacuum taps, clutch lines and turbo oil feeds rather than on a main fuel supply. Steel is the practical, budget-friendly option for MIG or TIG welding into mild steel fuel tanks, steel sumps, chassis rails and mounting plates. Weld all the way around for a proper seal, and keep the heat moderate so the flare seat stays flat. Any AN4 hose end or adapter threads straight on and seals on the 37-degree flare, so no sealant is required.