Will the Down Under Wonder work in any shower?
Yes. It has a standard 1/2" female pipe inlet so it can be installed on any standard shower fitting. You can also use the Wonder Arm with your existing shower head.
Do I have to hire a plumber to install it for me?
You can install it yourself very easily because it's designed to be installed with very little actual plumbing work. The only time you need a wrench is to remove your old showerhead. The products come with simple, easy to follow installation instructions.