Do not risk using extensions as they typically do not function properly. This is a built-in real mini-catalytic converter. The O2 check engine light (CEL) fixture with a miniature unit will make your ECU believe the original catalytic converter is still installed. When the catalytic converter is removed, the rear O2 sensor detects higher temperatures and increased unburned fuel flow, which can trigger the check engine light (CEL), usually 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 may take time to stabilize. However, CEL alerts can also stem from O2 sensor issues, such as an overly sensitive sensor, which may still activate the light even after installation. Additional error codes may still occur. Therefore, this CEL simulator (sometimes referred to as a mini converter) cannot resolve all CEL-related issues. It is designed to address the most common P0420 code related to catalytic converter efficiency.Features: 1. Threads are precision-machined with specialized tools for accurate fitment. 2. Simple design with high-quality materials, resistant to deformation and rust. 3. Universal fit for most vehicles with 18mm x 1.5 O2 sensor bung openings. 4. Constructed from high-strength metal for durability. 5. Easy installation with direct bolt-on design; no modifications required.Condition: New Type: O2 Sensor Spacer Adapter Thread: 18mm x 1.5 Material: Metal Color: Silver Package Contents: 2 x Oxygen Sensor Spacer Adapters Note: The package includes only the items listed above. Other accessories are not included. Note: Lighting and display differences may cause slight color variations between the product image and the actual item. Measurement may vary by +/- 1-3 cm.