The reverse temperature sensor adds a completely different function to your GSR 2 and lets you experience a fascinating new area of biofeedback technology - temperature biofeedback. Generally, increasing levels of stress lessen the blood flow to your hands and feet. This causes decreases in hand and foot temperatures. With the monitoring help of the thermistor, you can learn to control that temperature. It's amazing when you realize what you’re basically controlling is the dilation and constriction of blood vessels in your arms and legs.