what is the proper gasket/ring between the upper cat and lower cat pipe

[cfauvel]

2007 altima with 2.5L engine.

I order the parts from Rockauto, I ordered the ring between the exhaust/pre-cat, and the pipe that holds the secondary cat.

I ordered two different mfg parts for the same position and got two different sizes.

I haven't taken the header off yet, and i'll use what ever ring that fits...but I'm not familiar with these solid looking ring. Is this a crush ring and is the right part or, should it be some fibrous material?


I bought part number 256-1125
http://www.rockauto.com/en/moreinfo.php ... 74&jsn=406
the other ring is smaller and the packaging states for earlier years...

just want to be sure it is a crush ring and not a solid fibrous ring.