O2 Oxygen Sensor Weld In Bung & Plug M18 x 1.5 Stainless Steel Adapt (4 Sets) 304 STAINLESS O2 OXYGEN SENSOR WELD ON BUNG PLUG M18 X 1.5 Vibrant Standard Oxygen Sensor Weld Bungs Mild Steel (M18 x 1.5 thread) Bulk Pack of 100 pcs. 10pcs M18x1.5 O2 Oxygen Sensor Weld On Bung Plug W Grandado Iron M18X1.5 O2 Oxygen Sensor Stepped Mounting Bung Plugs Oxygen Sensor. All Vibrant Performance exhaust bungs are made from the highest quality stainless and mild steel to ensure the utmost in quality for all professional aftermarket and O. E. M Exhaust projects.