Shell Rotella 550045126 1Gal Sae 15W-40 - T4 Triple Protection - Heavy Duty Diesel Engine Oil is designed to provide hardworking protection that adapts to your driving conditions. With millions of miles of accurate world testing, Shell Rotella T4 Triple Protection 15W-40 uses a proprietary formula exclusive to Shell. It is designed to protect against the most severe engine conditions found in modern low-emission engines and older, hard-working diesel engines. It is designed to effectively sustain the durability of emissions control systems where diesel particulate filters and after-treatment systems are used. Plus, it provides enhanced protection against viscosity loss due to shear and improved oil aeration. The exclusive low ash formulation helps protect the exhaust catalysts and diesel particulate filters found on the latest low-emission vehicles. Suitable for virtually all modern low-emission heavy-duty engines and older hardworking diesel engines.