It is based on the premise that our bio-field which extends around us in the shape of a torus - is the storehouse containing the records of all of our memories, embedded as energy and information in standing waves within this structure.

Traumatic experiences, whether physical, mental or emotional, give rise to distortions in these standing waves acting as a noise in the signal that can cause a breakdown in the order, structure and function of the physiology. The coherent frequency of the instrument acts therapeutically in a very targeted way when held in specific areas of distortion, inducing greater order into the system.  

Just to clear things up......
When we speak of vibration, we are merely using another synonym for frequency.  Different frequencies of energy reflect varying rates of vibration.  We know that matter and energy are two different manifestations of the same primary energetic substance of which everything in the universe is composed, including our physical and energy bodies.  The vibratory rate of this energy determines the density of its expression as matter.  Matter which vibrates at a very slow frequency is referred to as physical matter.  That which vibrates at specific higher speeds is known as subtle matter.  Subtle matter is as real as dense matter; Its vibratory rate is simply faster.  In order to therapeutically alter our subtle bodies or energy field, we must administer energy that vibrates at frequencies beyond our own.