Abstract: The invention relates to a fuel tank attachment comprising a first region (12) that has a first plastic (A), and a second region (35), wherein the second region has a blend of the first plastic and a second plastic (B), wherein the first and second plastics are not miscible, wherein the blend contains a compatibilizer to make the first and second plastics miscible, wherein the first and the second regions are integrally bonded to each other, wherein the first plastic is a fuel-resistant plastic, and wherein the second plastic is a non-fuel-resistant plastic.