Twin version, with two double inlet wheels on the same shaft, supported on light rectangular side frames of galvanised steel, welded on the scroll sides.  Ball bearings on electrically conductive rubber shock absorbers, inside inlet spiders.
Available from the size 7-7 to the size 18-18.
The standard fan can be freely rotated, to allow installation with orientation 0, 90, 180 or 270, as defined in ISO 13349.
