This is a direct-fit, bolt-on Flex-A-Lite® dual electric-fan system for 2003-2007 Ford Super Duty trucks with 6.0L diesel engine. Recover horsepower and boost your fuel economy by replacing your stock clutch fan assembly with this dual electric fan system. It features two 15-inch S-Blade electric fans and a Flex-a-lite Variable Speed Controller that varies the fan speed from 60-100 percent, depending on radiator temperature. These powerful fans move up to 6,800 cfm of airflow!