In "Small Cooling Fan" of choice, we tend to compare wind pressure and wind, air pressure and air volume for normal ventilation. Ventilation fan to overcome resistance within the travel, the cooling fan must overcome the air resistance generated pressure. This is the pressure. Pressure is an important measure of performance cooling fan. Pressure depends on the shape of the blades, area, height and speed, the faster the speed, the greater the fan. "Small Cooling Fan" relatively greater the pressure, duct heat sink design also better able to maintain the fan pressure. Air cooling fan air flow is sent or inhalation of the total volume of air per minute. In the same heat sink material, the air flow is a measure of the most important indicators of air-cooled heat sink cooling capacity. The larger the fan. The larger air volume, and more big "Small Cooling Fan" in the unit time can take more heat.