Don't take a chance on using an extension only as often they do not work, this is a real mini Catalytic Converter built into it. This O2 cel fix actually has a miniature catalytic converter built inside and will help that annoying check engine light you get after modifying your exhaust or removing your catalytic converter, and sometimes even when installing a high flow catalytic converter. As a result this will throw check engine lights (Cel, , ) typically the error codes will be P0420 ( System Efficiency Threshold Bank 1) and/or P0430 P0420 - System Efficiency Threshold Bank ). CEL Fix Check Engine Light Eliminator Adapter- O2 Sensor for auto. New and High Quality. Type:O2 Oxygen Sensor Adapter Surface treatment: electronickelling Thread: M18x1.5 Length: 58mm Function: check engine light fix Colour: silver Material: metal Size: 58x16x25mm Package Contents: 1 * O2 Sensor Adapter Extender Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. M18X1.5 O2 Oxygen Sensor Adapter with Filter Elements for Decat Hydrogen O2 Extender Spacer CEL Fix Check Engine This O2 cel fix actually has a miniature catalytic converter built inside and will help that annoying check engine light you get after modifying your exhaust or removing your catalytic converter, and sometimes even when installing a high flow catalytic converter. As a result this will throw check engine lights (Cel, , ) typically the error codes will be P0420 ( System Efficiency Threshold Bank 1) and/or P0430 P0420 - System Efficiency Threshold Bank ). CEL Fix Check Engine Light Eliminator Adapter- O2 Sensor for auto.