This week I installed the two Maxxair fans in the roof of my bus.

It was a bit nerve-racking cutting the holes in the roof because you only have one shot to get it right, but it turned out ok.
I still have to connect the wiring to the fans but will do that at a later date when I do all my electrical work. I have run the wires in conduit inside the ceiling and where they come out will be overhead cabinets so I will have full access to them when I need.
There is also a trim piece that goes around the fans on the inside but that gets installed once the ceiling lining is done.