Catalytic converter gasket - use ring or flat type?

I purchased a new exhaust for my 2007 Aveo 5 and the catalytic converter has both a ring gasket for both ends as well as a flat gasket. Do I use both on both ends, just the rings gasket or what? Don't want to have to take it apart twice.

Thanks,
Daryn

The ring alone will work fine. I don't think using 2 gaskets would ever be a good idea (for anything).

I just saw a thread where the factory exhaust was removed and in the pictures is both a flat gasket and a crush ring. Guess I'll just wait until we get a weekend in Connecticut where it doesn't rain and find out. I'll let everyone know what I find.

I can say for certain that the factory used only ring gaskets on my '05, and that's what I also used when I replaced the exhaust system. Not telling you what you should do, just what worked for me.