NMB DC Blowers are available in sizes ranging from 45mm to 145mm. A DC blower is a type of fan used in network servers and telecommunications systems with high impedance from back pressure. These types of fans contain a circular impeller within an enclosed cage, which is often referred to as a “squirrel cage”. This design allows DC Blowers to create directed airflow under high pressure conditions. A DC Blower has a more concentrated airflow in which the equipment pulls air in from the sides and forces it out at a concentrated 90º angle.