has many uses - i keep mine in my nostrils in the pollen season. but you can stick them other places too. its not just an o2 sensor. denso quality good and the fact copper anti-seize paste is included with each one means insertion and removal is that much easier.
appears to be working fine. hard to say if it had been preinstalled when I received it or not as the anti-seize was applied to the threads. Hope it lasts.