High Airflow for Efficient Large-Volume Cooling Air Series AF case fans perform best in unrestricted spaces with at least 3 cm (1.2”) of clearance, and they’re ideal for mounting at the rear or top of your PC case as exhaust fans for your PC’s motherboard and CPU, graphics accelerators, and other components that fill the case with heat. They work equally well as unrestricted intake fans for areas like side panels or bottom intakes. For high restriction areas like hard drive cages or in other tight spaces where there’s less air volume, check out our Air Series SP models of high static pressure fans.