are suitable for transporting larger amounts of air with smaller to medium-sized resistances.

They can be used, among other things, for

cooling devices, engines, etc.
air conditioning of rooms
ventilation and drying purposes
transporting cold and hot air
drawing off gases and vapours
additional ventilation of gas, coal or oil furnaces
increased drafts in chimneys
a very high output of air with only small resistances (V-types)
a rate of delivery between 110 and 3,600 m3/h
a rate of delivery at between 155 and 1,450 ppa