Total fitness body analysis digital scale is the perfect partner in helping you achieve your weight maintenance goals. Body fat %, total body water, muscle mass %, bone density and calories are calculated using Bio-Electrical Impedance Analysis. The technology allows you to easily calculate your body fitness by imputing info of gender, height, age, activity level and your weight. With bare feet, this technology sends low-level electrical signals through your body fat and then measures the resistance the signal encounters. This signal is perfectly safe and will not be felt. This scale is also programmable to be set to either traditional or metric system of unit measurements. Operates on CR2032 Lithium Battery (included).