Valvoline Premium Blue 15W40 Heavy Duty Engine Oil is endorsed by Cummins Engine Company and has been tested extensively by Cummins in stationary and on road engines. It provides advanced lubricant performance in modern, emissions treatment equipped diesel engines. It offers a long-life extended rain formula which helps maximize engine durability as well as after treatment cleanliness. It provides excellent performance in mixed fleet gasoline engines, pick up and delivery, city fleet and long haul over the road applications. It also meets the requirements for Tier IV off road engines and is backwards compatible with Tier III. This product meets CK-4, CJ-4, CI-4, CH-4, CG-4 and CF-4 performance requirements.