Universal, Multi-Purpose Fitting, Female 1/4" -18NPT Mild Steel Weld Bung (7/8" OD), Female 1/4" -18NPT Mild Steel Weld Bung (7/8" OD), STEEL WELD BUNGS, Weld Bungs, Vibrant Performance female NPT bungs are available in both aluminum & mild steel and range from 1/8" to 1" thread sizes., 1/4"NPTFemMSWeldBung.