Ok so here is the story I have been trying to get a o2 sensor from o'reilly and they have already messed up my order twice now.
First they sent me the universal o2 sensor which I did not ask for.
Then the second time they sent the third o2 downstream not the second one like I asked for.
Now they want $150 for the post-cat sensor, so I decided to find a cheaper price.

My question: Which o2 sensor do I need from rockauto for the post-cat o2 sensor right after the cat. There is so many. The one I think I might need has no description what so ever or any pic.
Any help I would be really thankful.

By the way I have a 99' maxima se not cali and it's 3 wires on o2 not 4.

 

I got all my o2 sensors off amazon(when you factor rockauto shipping) as it was cheapest at the time. I went for universals(only takes ~10 min max to splice the harness together with supplied connector) and paid around $39 each. They also have oe fit ones for ~50 iirc.