Fans with encapsulated ball bearings, 4-pole, equipped with a metal protective grille located on the inlet side. The shaped helix is made of aluminium alloy injected straight onto the rotor. The fans are produced with an external rotor motor with permanent capacitor. The square base is made of galvanised sheet steel. The motor speed can be adjusted by reducing the supply voltage using a variable speed controller. Application: air conditioning, air renewal and cooling of electrical and electronic equipment.