It would be located inside a vehicle e.g. car.
How do you know when your Catalyic Converter needs to be clean or needs to be replacsed
In the exhaust, close to the manifold(s)
If and when it becomes clogged.
There is only one thing you can do and that is to replace the clogged converter. There is no way to unclog it.
It reduces the amount of emmisions your car lets off
Replace
Removing a catalytic converter will cause a check engine light, lower power on a computer controlled vehicle, and is highly illegal.
PCV valve and catalyic converter.
They are in the exhaust system. Some have them before and after the catalyic converter.
I suggest you take your vehicle to a muffler shop or dealer for this repair.
you have 2 they are in exhaust head pipes are stainless steel
The one that fits which anyplace that installs and sells them can tell you.