how to find correct catalytic converter 2007 toyota tundra

I need to replace one of my catalytic converters on my 2007 toyota tundra. How do I find the correct one?

 

not trying to be a smart a$$ but have tried a local auto parts store or google for finding it online?

 

Yes, thanks smart butt. I am going to replace it myself and I am trying to figure out which brand is better Mosul, Walker are the brands I have found that fit on rock auto. I assume I should replace oxygen sensors when while I'm there. Should I also replace exhaust flange gasket?

 

Welcome from NY! I had good luck with walker in the past, make sure it's CARB certified, our tundra's are low emissions vehicles. I would try the old sensors first. Was it throwing codes for them? Yes always replace and gaskets. Good luck, john