The 4FN version is more aggressive than other full sized units and, as with the other versions, the fans are easily reversed which separates them from the others. This way you can very aggressively move air upwards or downwards which means that whether you set a component on top of this cooler, or the cooler on top of the component, you can easily direct air away from the component.This is a very aggressive and versatile fullsized (same width as standard components)cooling unit. It circulates air away from components thus protecting equipment from heat accumulations and failures. This unit also allows for, and provides more advanced and unique features. The basic version features two top-quality 92mm Levitation fans that are mounted using special mounting hardware which eliminates noise caused by normal fan vibrations. The unit operates on DC voltage and, by adjusting the voltage, can be run silently or more aggressively depending on the application. This unit is ideal for directly cooling amplifiers and receivers installed in cabinetry or rack systems and can also ventilate entire racks and entertainment centers.