Upgrade your basic, flimsy plastic oil fill cap in your Ford Powerstroke and or your Ram Cummins with this stylish Billet Oil Fill Cap from Sinister Diesel. This cap is not only better looking than the factory but is a durable option to keep dirt and moisture out of your engine. This cap is constructed of CNC machined solid billet aluminum featuring signature Sinister Blue anodized coating and is laser etched with the Sinister Diesel logo.