high airflow is lots of CFMs, you want high CFM on say a case fan, these are fans designed to move lots of air with minimal obstruction, Fans with lower CFM typically have a higher static pressure, THis is the pressure against the heatsink created by the airflow, this is generally designed for heatsink coolers, and cooling off heatsinks or coolers in general, as the higher the static pressure, the more turbulence and the greater the heat dissipation.