The Otto 128 tuning fork works by placing it directly on the body at specific points where your bones are able to act as a conductor for the vibrations. With this method it is possible to stimulate nerves and release muscular tension thorughout your body. The Otto 128 carrying case is made by hand with sustainably sourced felt and lined with soft merino 100 % virgin mulesing-free wool. The case also comes with a small pocket to store additional gem feet and the tool you need to remove/attach them.