All Tanita body composition monitors use advanced Bioelectric Impedance Analysis (BIA) technology. When you stand on a Tanita monitor, a very low, safe electrical signal is sent from four metal electrodes through your feet to your legs and abdomen. In segmental models, the four hand-held electrodes will provide extra readings for each leg, arm and abdominal area. The electrical signal passes quickly through water that is present in hydrated muscle tissue but meets resistance when it hits fat tissue. This resistance, known as impedance, is measured and input into scientifically validated Tanita equations to calculate body composition measurements. Depending on the monitor, body composition measurements are provided in under 20 seconds. Tanita body composition monitors with Advanced Dual BIA Technology use two different frequencies to capture your body composition data. By using different frequencies, even higher accuracy of measurements can be achieved.