Where does this gasket go...other than modulator pipe thingy?

[BullElk]

Could this gasket go anywhere else? I found it in driveway and don't ever remember taking of the modulator pipe thingy. Just wondering about any other possibilities.

Thanks

 

[Ridgerunner78]

Looks like O2 sensor to me.

 

[BullElk]

BAM!! Oh yeaaaaaa... That's it. I used new gasket. Thanks. That's exactly why I asked.