A few examples would be: Intercooler piping, Intake manifold, or even a custom overflow tank Weld bungs are most commonly used when needing to attach AN lines to areas that don’t currently have AN flare. A few examples would be KRD PERFORMANCE 2PCS Aluminum 3/4 NPT Female Weld On Bung, 3/4 NPT Weldable Fuel Tank Fitting, Natural 3 Inch Weld In Fill Neck Bung and Caps WLDFC3 Aluminum Weldable Fitting KRD PERFORMANCE 2PCS Aluminum 3/4 NPT Female Weld On Bung, 3/4" NPT Weldable Fuel 6061-T6 Aluminum Bung or wherever an NPT fitting is needed Snapklik.co : AC PERFORANC 4PCS 3/8" NPT Feale Weld On Bung Weldable Fuel Tank Fitting Aluinu Can be welded to aluminum valve covers, holding tanks, cylinder heads, oil pans, etc. Made of high performance lightweight 6061-T6 CNC machined billet aluminum