ID mystery sensor please

[ShaneHobson]

While pulling the oxygen sensors off my parts car I found two more sensors that don't appears in either of my parts book.

Attached photo shows my spare exhaust system, looking down from above with rear end at the top of the photo.

I've ID'd the two oxygen sensors toward the front of the car (bottom of photo) (please someone correct me if I'm wrong).

But the other two sensors higher up the photo (towards the back of the car) aren't shown in either of my parts book.
Can someone tell me what they are please ?

It's a JDM car.

Thanks, Shane