I have mine mounted on the pedestal of the passenger seat, horizontally. I
was watching ship shape tv, on speedvision two weeks ago, and they were
talking about fire extinguishers, the different types available and how they
work. They mentioned that the best way to hang them was in the horizontal
position, and that if it was vertical, to once in a while give it a shake,
just to keep the stuff inside smooth, FYI.