FFU manufacturers A fan filter unit (FFU) is a type of motorized air filtering equipment. It is used to supply purified air to cleanroom, laboratories, medical facilities or micro environments by removing harmful airborne particles from recirculating air. The units are installed within the system's ceiling or floor grid. Large cleanroom require a proportionally large number of FFUs. Units often contain their own pre-filter, website:http://www.adencn.com/ffu/