Temperature biofeedback is based on the fact that when we relax, our hands and feet get warmer. The actual blood vessels relax and allow more warmth to flow from the core of the body to the extremities. Research has shown that we can learn to voluntarily warm our hands from within and this produces deep states of relaxation. This Deluxe package provides you with precision digital numeric visual feedback, great audio feedback and a pocket stress check thermal biofeedback card that is also a great conversation piece. If purchased separately, off amazon, their cost could add up to $115.00