Do not use extensions as they may not function properly; this is a built-in mini catalytic converter. This O2 check engine light (CEL) fixture with a miniature catalytic converter helps the ECU detect the presence of an operational catalytic converter. When the catalytic converter is removed, the rear O2 sensor may detect changes in temperature and exhaust composition, potentially triggering a check engine light (CEL), commonly with diagnostic trouble codes P0420 (catalyst system efficiency below threshold, bank 1) and/or P0430 (catalyst system efficiency below threshold, bank 2). This device is intended for off-road use only and is not legal for use on vehicles operated on public roads. It may require some time to become fully operational. Note that CEL alerts can also result from O2 sensor malfunctions or over-sensitive sensors. In such cases, the light may remain on after installation, possibly generating additional error codes. Therefore, this CEL simulator (commonly referred to as a mini cat) is not guaranteed to resolve all check engine light issues. It is specifically designed to address the P0420 code related to catalytic converter efficiency, which is the most common cause. 1. Threads are precision-machined using specialized tools for accurate fitment. 2. Simple design constructed with high-quality materials, resistant to deformation and corrosion. 3. Universal fit for most vehicles with 18mm x 1.5 O2 sensor bungs. 4. Made from high-strength, durable metal. 5. Easy installation with direct bolt-on design; no modifications required. Condition: New Type: O2 Sensor Gasket Adapter Thread: 18mm x 1.5 Material: Metal Color: Silver Package Contents: 2 x Oxygen Sensor Adapters Note: The package includes only the items listed above. Other accessories are not included. Note: Lighting effects and display settings may cause slight variations in color between the image and the actual item. Measurement may vary by +/- 1-3 cm.