... by external rotor motor,powder coated in black 2,Thermal protector inside of motor 3,Plastic&galvanized steel impelle Circular ... Drived by external rotor motor,powder coated in blackl Thermal protector inside of motorl Plastic&galvanized steel impellerl Sheet steel ... easy for maintenance. No need fan room. Controllable speed Thermal protector inside of motor Insulation Class F, Protection Class IP44 Lower ...