... .3micron 3.Flexibility for installation 4.Clean Room Fan Filter Unit Clean Room Fan Filter Unit FFU, short for ... top of the module, and exhausts filtered clean air vertically in a unidirectional(laminar) ... controlling. FFU is installed on ceiling of clean room (25%to100% cover rate), general dimension ... Class 100,000 cleanrooms, even forming ultra clean line, clean closet and etc… 1. Nice appearance , ...