Terraillon uses fast, secure and reliable technology that has been medically attested - the body fat analyser. Enter your age, height and sex before stepping onto the scales. A low-intensity current passes through your lower limbs - sensors are located on the platform of the scales - and measures the resistance or the 'impedance' to this signal. By differentiating between the impedance of lean and of fatty tissue, the device calculates the percentage of fat in the body (fatty mass contains less water than lean body mass and therefore provides a greater resistance to the current).