Keeping you Ready for the Road Ahead , the Delco Remy 40SI 12V 300A Pad Mount Brushless Alternator ensures you are Ready for the Road Ahead , with its best-in-class efficiency rating that requires less engine horsepower, while delivering measurable fuel savings. The design of the 40SI series specifically addresses vehicle applications that require high electrical output, like those experienced from APUs, liftgates, and other demanding equipment. This brushless heavy duty alternator raises the bar with high amp output for your truck. In addition, the housing of the 40SI alternator acts as a heat sink which allows for greater heat dissipation, thus allowing the alternator fan to cool more efficiently. Equipped with Remote Sense technology, this heavy duty brushless alternator also uses a second wire that interprets actual voltage from the battery and increases voltage output to ensure a constant power of 14 volts at the battery. Thus, your battery is brought to a fully charged state in half the time. FleetPride is your First Click in Heavy Duty .