The Glucoject Dual S home glucose testing device employs the principles of what is known as the gate theory of pain. When using this device, the pain usually associated with pricking one's finger is either significantly reduced or cancelled out altogether. The Comfort Zone Technology used in the design of the Glucoject Dual S device features eight raised points that, when pressed against the skin, stimulate the sensory nerve endings in the fingertip. These nerve endings, which are responsible for sending touch and pressure messages to the brain, tell the brain that a comfortable and non-painful action is taking place in the skin. These messages tend to mask or cancel out any pain messages that would be sent when the skin is penetrated, an allow a virtually pain-free blood sample to be taken.