Male end threads into existing 18x1.5 O2 bungs. Bolt-on installation—no cutting or modification of stock wiring required. Installation: This oxygen sensor restrictor is NOT for use with the primary (upstream) oxygen sensor (sensor located before the catalytic converter). Quick and easy installation—no modifications needed. Usage: This oxygen sensor restrictor is designed for off-road race/track use only. It helps prevent the check engine light (CEL) / malfunction indicator lamp (MIL) from illuminating when the stock catalytic converter is removed. When installing a high-flow catalytic converter, increased exhaust airflow may trigger the CEL. An oxygen sensor spacer positions the rear (downstream) oxygen sensor farther from the exhaust gas stream, reducing the likelihood of CEL activation. Note: Some vehicles may require an ECU reset if the CEL was previously triggered. This product is compatible with your specific vehicle application. The kit allows for precise, customizable positioning. Our oxygen sensor extender kit is machine TIG welded for accuracy. Threads are precision cut to ensure a secure, leak-free seal and reliable sensor readings. Fits all M18x1.5 threaded oxygen sensors. Fits all vehicles and exhaust systems with M18x1.5 oxygen sensor bung threads. Easy bolt-on installation—no modification required. Color: Silver Material: Steel Size: 22 x 32 mm Package Contents: 6 x oxygen sensor bungs Note: Color may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 mm.