The new bioweigh-usb body composition scale from american weigh allows you view a complete breakdown of your body fat, water, muscle, and bone. the scale works on the principle of bia (bio impedance analysis). by passing a safe electrical current through your body via the metal contacts and using weight, height, and age data, your lean/fat-free body mass is calculated. this is then subtracted from your body weight to obtain body fat mass. you can use the included usb cable and weightrak software to upload your scale’s stored data to a pc. note: although the scale uses a safe electrical current, those with pacemakers or other electronic implants should not use this scales body fat feature.