Gaskets for catalytic converter
 

Hello all,
I'm changing the catalytic converter on my 1998 Blazer LT, but wasn't sure of what kind of gaskets I needed to get. Took the old one off last night and it appears there are two flat, triangular-shaped gaskets - one on front and one on back. Now I've searched all the auto parts stores locally and most have one size, some have two different and one's special order, and some have ones that look like a metal donut that I'm guessing presses in between. Any suggestions on where I should look to get both gaskets? Sizes? The cat I ordered is a direct-fit Walker 15827. It seems to line up and the flanges are the same size. I'm just not sure what gaskets I need to get.

Any help would be appreciated.