Engineered for both silent operation and maximum airflow, BitFenix’s Spectre LED PWM 120mm Case Fan will keep your CPU running cool without sounding line an airplane hangar. Spectre LED PWM Fans are designed with sickle fan blades that enhance airflow without producing excess noise and are outfitted with orange LEDs. The on-the-fly LED light switching feature requires an optional BitFenix Hydra Pro Fan Controller or Survivor Chassis to turn the lights on and off with a press of a button. It can also be used as a regular LED fan with jumper-selectable on/off. Furthermore, this fan utilizes pulse width modulation technology that better cools your system by letting your computer adjust the fan speeds.