Product Description 4 X CEL Fix Check Engine Light Eliminator Adapter, O2 Sensor Extension Bung 45mm Check Engine Light fix is basically a way to space out the O2 sensor so that it still reads SOME exhaust gaes but it removes the O2 sensor from the direct flow of the gaes as to make the ECU believe there is a restriction in the exhaust gaes such as by a Catalytic Converter. This spacer only minimize the chance of CEL. Some vehicles will need their ECU reset if the CEL is triggered before hand. FOR OFF ROAD USE ONLY Features Made from high-grade plated steel Simply threads into the existing bung Length: 45mm Package Included: 4 Pack of CEL Fix NOTE: If you have any questions, please feel free to contact us. We will respond you as soon as poible.