The KidsTemp; SportsTemp; BodyTemp - Thermostrip effectively reflects the core temperature of the brain and producing a clear, accurate, easy to read yellow color indicator. The easy-to-use, 2 inch, self adhesive Thermostrip is worn on the forehead or upper chest (if the upper chest is used, then add one degree to the reading, as the Thermostrip is further from the brain). It is scientifically proven to reflect the "physiology" of the brain, determining if we are training within an appropriate intensity range / zone.