The Ambient Weather WS-2902C Weather Station is a very reliable, capable, and connected weather station with some excellent features, but for some reason like so many others, it uses an LCD screen with a very limited viewing angle. It provides means to mount it on a wall, but unless you're standing at just the right altitude relative to the mounting point, this renders the display unreadable.
This angler does two things. First, it tilts the unit down at about a 30 degree angle, making it a good viewing angle if you're seated and looking across the room at it mounted at a reasonable height that clears furniture. Second, it makes mounting it much easier; you can drill holes for the mounting, affix it, and then simply snap the display into place.
In my case, as you can see in the picture, it's mounted on the middle of a double window, so there's a slim 'rise' which I have left a gap for at the bottom, but if you're mounting it on a flush surface, that gap won't cause you any problems.