Standard DC Brushless fan sizes include 60mm, 70mm, 80mm, 92mm and 120mm. The amount of airflow that a fan generates is measured in cubic feet per minute (CFM), and the rotational speed in revolutions per minute (RPM). Static pressure is measured as inches of water (H2O). DC Brushless fans are found in a variety of applications, including computing, servers, telecommunication cabinets, and any type of equipment where the need for thermal control is necessary for the improved reliability and life extension of the components that are included in the system. Now that the price point of a DC Brushless fan has become more reasonable, the many advantages of the DC fan over the AC had made it the top choice for CPUs.A prime advantage a DC Brushless fan has over an AC fan is a longer life span.A DC Brushless fan also consumes up to 60 percent less power than an AC fan. In fact, experts have proven that a 10 C increase in fan temperature can reduce a fan s life by as much as 20,000 hours.Another big advantage of a DC Brushless fan over an AC fan is that the speed of DC fans are directly proportional to voltage, thus allowing them to run at the speed required for adequate cooling.In essence, DC Brushless fans direct heat outside of a motor, keeping your device/CPU running at an optimum level.