Male end threads into existing M18 x 1.5 O2 bungs, bolt-on design requires no cutting or modification of stock wiring. This oxygen sensor restrictor is not intended for installation with the primary oxygen sensor (sensor before catalytic converter). Quick and easy installation with no modifications needed. This oxygen sensor restrictor features adjustable gas flow inserts. Designed for off-road racing or track use only. Helps prevent the check engine light (CEL) or malfunction indicator lamp (MIL) from illuminating when the stock catalytic converter is removed. When installing a high-flow catalytic converter, the check engine light may illuminate due to increased airflow. An oxygen sensor spacer positions the rear oxygen sensor away from the direct path of exhaust gases. An extension spacer may reduce the likelihood of CEL activation. Some vehicles may require ECU reset if the CEL has already been triggered. This product is compatible with applications using M18x1.5 threaded oxygen sensors. The kit allows for proper and customizable installation positioning. Oxygen sensor extender is TIG welded for precision fit. Threads are precision-cut to ensure a proper seal, prevent exhaust leaks, and maintain accurate sensor readings. Fits all vehicles and exhaust systems with M18 x 1.5 oxygen sensor ports. Durable, corrosion-resistant plating. Color: Silver Material: Iron Size: 22 x 32mm Package Contents: 4 x Oxygen sensor bungs Note: Light and display settings may cause slight color variation between the image and the actual item. Measurement may vary by +/- 1-3 cm.