By using the principle of bioelectrical impedance analysis (BMI), this analyzer sends an extremely weak current through your body to accurately estimate body fat percentage and body weight. Just stand with your feet slightly apart, grab the handles, enter your stats and the monitor will display your BMI assessment in low, normal, high and very high ranges ” and it only takes seven seconds!. Additional body mass index reading offers extra tracking ability. Stores personalized information for up to nine people. Athletic mode provides accurate results for athletes. Guest mode let”s others perform a quick measurement without storing a profile. Height: 34″ to 66″; Weight: 23 to 440.5 lbs.; Age: 10-80 years; Athletic Age: 18-60 years. Uses two AAA batteries (included).