The FDC4-2T Rackamount Panel with Four 3.15" Fans from Lowell Manufacturing features a variable-speed thermostat probe that automatically activates four 3.15" fans, increasing and decreasing speed as it adjusts to ambient temperature. This power-saving feature ensures efficient fan operation and minimizes fan noise while saving wear and tear on the unit. Additionally, the panel offers a universal input voltage of 100-240 VAC that can be used almost anywhere in the world with the included plug adapters.