Bioelectrical Impedance is a technique where sensors are applied to the skin and a weak electrical current is sent through the body to measure it's electrical resistance. The measurement is used to estimate body fat, lean body mass, and body water. How the measurements are determined are by the electrical current because fat tissue is lessor of a electrical conductor versus lean body mass. If a person has more lean tissue then the electrical conduction will be easier. This technique is not used often because it cannot be used on everyone due to all of the equations used for electrical testing. A person's results may be off by 10% or more.