This is the right gasket for Duramax, between the cat and particulate filter. ID and hole pattern were correct. Caveat: Revain lists FelPro 61379 as "frequently bought with it". Judging by the picture, without size or scale, it looks like another gasket on the back of the DPF to the muffler flange. But 61379 is NOT a suitable gasket for the DPF flange/silencer.