Biofeedback - Galvanic Skin Response - GSR 2 biofeedback unit : The small, hand-held and self-contained GSR 2 is a Galvanic Skin Response monitoring device for home biofeedback. The GSR 2 precisely monitors your stress levels by translating tiny tension-related changes in skin pores into a rising or falling tone. By resting two fingers on the sensing plates, you learn to lower the pitch and your stress level. Features: 9V battery (included). Ergonomically shaped for a most comfortable and natural grip. Provides tonal feedback through speaker or earphones. Included is a user manual with a download link to the MP3 audio file.