This O2 sensor adapter is designed for off-road use only and features a built-in mini catalytic converter. It helps prevent engine check lights that may appear after modifying or removing the catalytic converter, including when installing a high-flow unit. The device works by simulating the signal of a functioning catalytic converter to the ECU, which can help avoid error codes such as P0420 or P0430 related to catalyst system efficiency. When the catalytic converter is removed, the rear oxygen sensor may detect higher temperatures and increased unburned fuel flow, potentially triggering the check engine light (SES) and diagnostic trouble codes (DTCs). This adapter with a mini catalyst can help manage these signals under certain conditions. Product Name: Car Oxygen O2 Sensor Adapter Product Size: As shown in images Product Color: As shown in images Product Material: Metal Thread Specification: M18 x 1.5 Packing List: 1 x Adapter Package Weight: 40g Note: All images are professionally edited. Due to differences in lighting conditions and display settings, there may be slight variations between the product images and the actual item. Manual measurements may also result in minor deviations, which do not affect functionality.