Version supported on light rectangular side frames, made 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 up 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.
