Where is the 02 sensor bank 2 sensor 1 on 2004 subaru outback 3.0?

On a 2004 Subaru Outback 3.0, the O2 sensor bank 2 sensor 1 is located on the exhaust manifold of the driver's side (left side) of the engine. This sensor is positioned upstream, before the catalytic converter, and monitors the oxygen levels in the exhaust gases for that bank of cylinders. To access it, you may need to lift the vehicle and work from underneath or reach from the top of the engine.