double inlet, direct driven with a brushless DC external rotor motor and including an external commutation unit EKE 10. Lap-jointed scroll housing made from galvanised steel sheet, with screwed brackets for different handings, and flange at discharge. High performance impeller with 11 backward curved laminar blades inclined obliquely to the shaft axis, welded in postion and painted. Cut off plate inclined obliquely in opposition to blade inclination. Inlet cones matched to the impeller to reduce entry losses. Impeller directly mounted on the rotor of the brushless DC motor in IP 54 type protection, completely maintenance free, statically and dynamically balanced to DIN ISO 21940-11, vibration isolated motor mounting. Connecting cable with 1,25m flying leads. Variable speed, optimized and approved for operation with an external control unit. Performance data in according DIN 24166 tolerance class 2 (BS 848 Class "B").