On ODB-II vehicles (96+), the ECU has two O2 sensors for diagnostic purposes. The first O2 sensor is located before the Catalytic Converter. This O2 sensor is responsible for all the Air/Fuel tuning and is imperative to the operation of the vehicle.

This Steel O2 sensor extender is basically for keeping the O2 sensor out of exhaust pipe. These also work when running a hi flow cat or a test pipe. It's a very simple 10~15 mins installation, This extender will fit most O2 sensors with 18mm thread size.