matt wrote on 09/02/09 at 09:23:25:I didnt think mine had one since i had never actually removed it before, after i ordered one i realized i had one, replaced it anyway.
It's SUPPOSED to be replaced with a new one every time you take off the header pipe, because it flattens out with just one install. HOWEVER, I have re-used it with no noticeable problems except maybe slightly more popping. OR, I have put in two used ones instead of one new one, and that seems to work okay too.