Temperature is detected when the Thermo is placed on the forehead. A display on the side will show body temperature in Celsius or Fahrenheit and will glow green, yellow, or red depending on whether or not the temperature readout indicates a medical problem. With Thermo, taking the temperature of a sleeping child, and evaluating its fever in the dark is incredibly easy. The device is powered by two AAA batteries that should last up to two years. By expanding into this important health measure, Withings is further delivering on its mission to reinvent personal health management and is paving the way for a new patient-physician relationship where accurate and meaningful data allows for better care.