New OEM Nissan Left Downstream (Rear) Oxygen Sensor for all Nissan 350Z's and Infiniti G35's equipped with the VQ35DE Engine.

Right Rear oxygen sensors can be found HERE.

Installed after the catalytic converters on the catalytic converter pipes, these sensors often prove to be extremely difficult to remove without destoying the threads when installing an aftermarket set of catalytic converters or test pipes.  These sensors are also referred to as an "Air-Fuel Ratio Sensor" by Nissan.

Z1 Motorsports recommends the usage of an anti-seize compound on the threads of the oxygen sensor to make future servicing much easier.