Stay on top of your training by keeping track of your weight regularly whether you're working towards a goal or just maintaining. When you step onto Garmin's Index Smart Scale, don't expect to see a shaky needle trying to make up its mind about how much you weigh like any other Garmin product, the Index is capable of recording a host of metrics. In addition to weight, the Index measures BMI, body fatwater percentage, bone mass, and muscle mass. It's also enabled with ANT and Bluetooth compatibility, so you can wirelessly upload your data directly to GarminConnect and analyze it against your goals and alongside workouts By giving you access to more than just arbitrary BMI measurements and weight, you receive a more well rounded idea of your strengths and weaknesses, which is more effective than relying on weight alone. The scale can store profiles for up to 16 users, which makes it useful for training groups and families, and it runs on four included batteries for up to nine months.