Review on High Output Grey-Black Dual Radiator Fan by Derale Performance - 16838 by Stephen Thomas

The construction itself is very good and as another user pointed out the hardware that comes with the kit isn't exactly universal. These things are SUPER loud (e.g. annoyingly loud) and pull out a TON of juice. I expected this behavior and installed a powerful Powermaster alternator. The fans are stunned to be running individually, and oddly, the revs still stumble a bit when the second fan kicks the truck. Whoa, not cool. If you want to use this fan assembly, you need to buy a PWM controller. I do not recommend the Derale device as the reviews are far from favorable. I'm adding an Auto Cool III PWM controller to keep temperatures constant instead of dealing with fans turning on and off at full speed.