The Ace Race Parts brand of metric Oxygen (O2) Sensor Bungs is precision machined using solid CP2 Titanium bar stock and work with all standard O2 Sensors that use a M18 x 1.5 thread. This specific O2 sensor bung fitting is coped to fit 1.500" OD to 2.500" OD tubing; however, it can easily work with other tube and even pipe size diameters. Our O2 sensor bungs are high quality CP2 Titanium options for custom exhausts, downpipes, and OEM repair fabrication projects.