This O2 sensor adapter is designed for off-road use only and helps prevent engine check lights from appearing after exhaust modifications, such as removing or replacing the catalytic converter. It features a built-in mini catalyst that can signal the ECU to recognize the presence of a functioning catalytic converter. When the catalytic converter is removed, the rear oxygen sensor may detect increased temperature and unburned fuel flow, which typically triggers diagnostic trouble codes such as P0420 or P0430 related to catalyst system efficiency. This device may help avoid these error codes by simulating normal oxygen sensor readings. Product Name: Car Oxygen O2 Sensor Adapter Product Size: As shown Product Color: As shown Product Material: Metal Thread Specification: M18 x 1.5 Packing List: 1 x Adapter Package Weight: 40g Note: Images are professionally graded. Due to differences in lighting and display settings, actual product color may vary slightly. Measurements are manually taken and may have slight variations, but this does not affect functionality.