The Ace Race Parts brand of metric Oxygen (O2) Sensor Bungs is precision machined using CP2 Titanium material and work with all standard O2 Sensors that use a M18 x 1.5 thread. This specific O2 sensor bung fitting is a Saddle Style Bung. Our O2 sensor bungs are high quality CP2 Titanium options for custom exhausts, downpipes, and OEM repair fabrication projects.