①. Male end threads into existing M18 x 1.5 O2 Bungs, Bolt-On, no cutting or modification of stock wiring like an electronic CEL FIX / MIL Eliminator. ②. Installation: This Oxygen Sensor restrictor is NOT to be installed with primary oxygen sensor (sensor before catalytic converter), Quick and Easy Installation with no modifications needed. ③. Usage: This Oxygen Sensor restrictor CEL Fix/Fouler with adjustable gas flow inserts. (Check engine light), For off-road race/track only, prevent CEL (CHECK ENGINE LIGHT) / MIL (MALFUNCTION INDICATOR LAMP) from illuminating when removing the stock catalytic converter. When installing a high flow catalytic converter on your car or truck your check engine light (CEL) may illuminate due to an increase in airflow. An oxygen sensor spacer spaces out the rear oxygen sensor from the path of exhaust gases. A extension spacer only minimize the chance of CEL. Some vehicles will need their ECU reset if the CEL is triggered before hand. ④. This product will work on your specific application. This kit allows for a proper and customizable installation position. Our oxygen sensor extender kit is machine TIG welded for a precise fit. The threads have been precision cut for a proper seal to prevent exhaust leaks and maintain proper sensor readings. ⑤. Fits All M18x1.5 threaded Oxygen sensors. ⑥. Durable corrosion resistant plating, Fits All vehicles and exhaust systems with M18 x 1.5 oxygen sensor holes. ⑦. For Usage Of Vehicle Spark Plugs Spacer to eliminate check engine light. ⑧. Easy Installation: Straight bolt-on, no modification needed. Very easy to install. ⑨. colour: Silver ⑩. Material: iron ⑪. size: 22*32mm ⑫. Package Contents: 4 * oxygen sensor bung ⑬. Only the above package content, other products are not included. ⑭. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.