Alluminum fish scale, if you are looking to replace it with new genuine parts then don't bother, none of the parts are avalible from Audi, apparently they have gone over to Audi heritage which basically means if any are avalible the price just doubled, this trim was only avalible on the B6 as was replaced on the B7 by brushed aluminium, I had this fitted in my B6 but in the end I bought some cheap wooden look ones and had them hydro dipped in carbon affect.