The 12" F5 High output In Line Fan - 1880CFM features a specially engineered aerodynamic design and mix-flow technology for an unheard of level of performance and efficiency. These fans are powerful. The 12" F5 High output In Line Fan - 1880CFM features a specially engineered aerodynamic design and mix-flow technology for an unheard of level of performance and efficiency. These fans have powerful internal drive motors, maintain high CFM ratings, are aerodynamically designed, feature UL recognized components, and an attached 8 ft power cord and mounting brackets.