More like a complete kit than a single part, our diesel oxidation catalysts include gaskets and mounting hardware for a complete installation. Since this part is a direct replacement, the exact fit adds another layer of efficiency and convenience. Product Features:Ductile iron or stainless steel construction to ensure long-lasting durabilityReplacement regulates exhaust emissions and turns off check engine lightNo special tools requiredManufactured to strict engineering quality standardsProduct might not be available in all states due to local laws.