1. This kind of O2 battery repair actually has a built-in micro catalytic converter, which helps to get rid of the annoying engine check that appears after replacing the exhaust gas or removing the catalytic converter sometimes even when installing a high-flow catalytic converter light.2. Only when they do not work, you can try to expand, this is the built-in real mini Catalyst.3. This kind of O2 battery device with a mini cat will deceive your ECU into thinking that a stock catalytic converter is still installed. When you remove the catalytic converter, the rear oxygen sensor will see a higher temperature and a greater flow of unburned fuel.4. Therefore, this will trigger the inspection of the engine lights Cell, SES, DTC, usually the error code is P0420 catalyst system efficiency is lower than threshold group 1 andor P0430 P0420-catalyst system efficiency is lower than threshold group 2. For off-road use only Specification:Product name: car oxygen O2 sensor adapterProduct size: as shownProduct color: as shownProduct material: metalThread specification: M18 X 1.5Packing list: adapter*1Package weight: 40g Note:All pictures are professionally graded, but due to different ambient light and different display device settings, there may be some deviations between the pictures you see and the items themselves. beg to be excused.The data is manually measured, there may be some deviation, but it does not affect the use.