<p>An exhaust after-treatment system including a first exhaust treatment device having a first mounting surface and a second mounting surface, and a second exhaust treatment device and a third mounting surface and a fourth mounting surface. A first mounting structure is attached to the first mounting surface of the first exhaust treatment device, and a second mounting structure attached to the third mounting surface of the second exhaust treatment device, wherein the second and fourth mounting surfaces are secured to each other.</p>