120mm fan mount for 110x55 retangular ventilation duct

I exported a "strait" option that allows mounting the ventilation duct in line with the fan if you need that. 

The “side” version is the one I used to extract air from a cabinet as shown on the pictures. The cabinet is used a cat litter box :-) … Ventilation is very effective to eliminate any smell and the rectnagular duct looks much cleaner than a round alternative.