In general, a fitness tracker's goal is to help you actively monitor your health using the latest and greatest technology.
You wear it -- some must stay on your wrist, others can clip into your clothing or be worn as jewelry -- and it, at minimum, automatically tracks your daily steps, plus distance and calories burned. The tracker then uploads that information to an associated smartphone app, where you can access it, set and track goals, compete with friends, and otherwise use it to better your overall health.
Those are just the basics, however. Additional qualities depend on the tracker you select, and can include physical draws, such as the ability to wear it up to 50 meters underwater or go long periods without charging. Performance perks can include monitoring heart health and waking you up at an optimal point in your sleep cycle.
Here are three popular wearable fitness trackers, and the defining qualities of each.
UP3 by Jawbone is an adjustable, one-size-fits-all bracelet made of black, medical-grade hypoallergenic rubber. Available with silver accents. (Red coming soon). $180
Battery Life: Lasts up to seven days before needing to recharge Water resistance: Up to 10 meters -- OK in the shower or swimming Uploading to app: Wirelessly and automatically
Misfit Shine is an aircraft-grade aluminum disc, not much larger than a quarter, ringed in teensy LED-lit holes, which display the time and your progress toward your daily activity goal. It comes in 9 colors, and can be snapped into a sport or leather wristband, a clasp to clip onto your clothing, or a necklace. $100
Battery Life: Runs on a watch battery you replace about every six months Water resistance: Waterproof to 50 meters Uploading to app: Wirelessly, by placing the Shine disc on your smartphone
Misfit also makes the Flash ($50), which has all the same qualities, except it's made from soft-touch plastic, is waterproof to 30 meters (rather than 50), and comes in seven bright colors.
Fitbit Charge HR is a colored, flexible elastomer band with a narrow OLED-display strip and surgical-grade stainless-steel buckle. It comes in three sizes and four colors. $150
Battery Life: Lasts up to five days before needing to recharge Water resistance: Sweat, rain, and splashproof, but not for use in the shower or while swimming Uploading to app: Wirelessly and automatically