This Lever Rocker is designed for use with Cummins 11L M11 CELECT ISM QSM engines. It is made of durable steel and is a direct replacement for part number 4003912. The rocker arm is a vital component for the engine's valvetrain system and this one is sure to provide reliable performance. The rocker arm is compatible with the Cummins brand and is designed to fit the specified engine model. It is not a vintage part and has not been superseded. This rocker arm is a great choice for those looking to replace a damaged or worn out valvetrain component.