I completely agree that the documentation is terrible and nonsensical. Plus it is "non-formatted" and looks like maybe it once actually was before being stripped of all formatting. There is no PDF manual on their web site.After 1/2 hour I still can't get the display mode to change from degrees C to F. Also, the altimeter sits there and fluctuates between -1 and 6 feet. Why or why? I am upstairs in a house that sits around 30 feet above sea level. The manual says nothing about calibration of altitude except to say that you can "set the current sea level pressure reading". What the heck is that supposed to mean and how would I know what it is supposed to be anyway?