Axial high-performance fan, cylindrical tube sleeve, smooth ends, directly driven. Tube sleeve made of galvanized sheet steel, with two reinforcing beads running around the circumference and protective grille made of plastic. Impeller with 7 blades made of thermoplastic. High efficiency, low operating noise. Vibration-free operation due to dynamic balancing according to quality level G 6.3 VDI 2060 and DIN ISO 1940. Three-phase squirrel-cage motor, with Dahlander winding (pole-changing), closed design, maintenance-free, sealed, low-noise ball bearings with long-term lubrication.