Brand: Derale Cooling Products Manufacturer's Part Number: 66838 Part Type: Fans， Electric Product Line: Derale PWM Electric Fan Powerpacks Summit Racing Part Number: DER-66838 UPC: 00083295668384 Puller: Yes Pusher: No Fan Diameter (in.): 12.00 in. Fan CFM Range: 4，000-4，099 Maximum Fan CFM: 4，000 cfm Fan Quantity: Dual Electric Motor Type: Brushless Height (in.): 17.000 in. Width (in.): 28.250 in. Thickness (in.): 4.000 in. Number of Blades: 7 blades Blade Material: Plastic Blade Color: Black Shroud Color: Natural Shroud Material: Aluminum Amp Draw: 49.60 amps Air Conditioning Relay Included: No Mounting Brackets Included: Yes Mounting Hardware Included: Yes Quantity: Sold individually. Notes: Includes built-in pulse width modulation controller. Derale PWM Electric Fan Powerpacks Get complete control of your engine temperature! Derale PWM electric fan Powerpacks have integrated their high-performing PWM fan controllers into the fan units. The PWM fan controller features built-in soft start technology and utilizes pulse width modulation to constantly adjust electric fan speeds from 0-100%. This maintains the optimal engine operating temperature while allowing the fans to operate at the percentage needed， instead of 100% all the time. By using the fans at the percentage needed component life is increased and amperage spikes are eliminated. The Powerpacks use high output electric fans incorporated into precision engineered shrouds. The Derale Performance Powerpacks are available with single or dual fans and can conquer the most difficult cooling conditions.