Fitbit Flex : Wearable design with an impressive smartphone app

The FitBit Flex

FitBit Flex (Photo: Mat Honan / Wired )

In well-defined markets, it’s rare to see a breakthrough device. And yet here we are. There are a lot of sleep and activity trackers to choose from right now, but none better than the Fitbit Flex. It is the most wearable, best-syncing device in the scrum, with the best app to boot. And it does all this at a great price.

Rating: 9/10 Nearly flawless

The Flex is very similar to the Fitbit One, but smaller and housed and without a display. And instead of wearing it on your belt, bra or pocket, you slide it in and out of a slim, rubberized wristband. The band is extremely basic, and it lacks the design elements of the Jawbone Up or the display of the Nike+ FuelBand. Other than the LED lights it uses to give you feedback, it is visually flat. In short, it’s not obviously some sort of sensor.

What it is, however, is highly wearable. A fitted clasp keeps it locked on your wrist securely. Most of the time, at least — I managed to dislodge it once while getting my squirming two year old out of a car seat. But I found it stayed on better than the Up. Similarly, there are no parts to lose, unlike the Up’s end cap that has a tendency to pop off and disappear over time. It’s waterproof-ish — while you can’t take it diving, you can wear it in the shower. In a huge improvement over the One, you don’t have to put it in an armband (it’s already in one) at night to track your sleep. That lack of visual flair also means it doesn’t look out of place with a suit, or a track suit. It comes in black. You can buy a three-pack of other colors if you want for an extra $30.

(See more: 4 great running shoes reviewed)

It also has a fantastic battery life. Fitbit says it was able to push performance by improving the algorithms the Flex uses to track movement and slice up the collected data. It shows. Fitbit says single a full charge should last about two weeks. I still have not run my review sample down yet after five days of use, and the battery indicator still shows a mostly-full charge of around 60-ish percent.

Fantastically, it’s able to operate on very low power even while performing great feats of syncing. The Flex uses a low-energy Bluetooth connection to talk to a USB dongle on your computer or, more miraculously, your iPhone or Android device. (At least a small number of Android devices, that is. Check to make sure yours is supported before throwing down cash.) If you’ve got your phone in your pocket and a Flex on your wrist, the latter will trickle data to the former all day long. You can check your progress in the app (and get notifications) or tap the device itself to activate the LED lights which indicate how far along towards your goal you are.

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Photo by Alex Washburn/Wired

The author wears a Fitbit Flex (in black) on his wrist, next to a Jawbone Up.

All of that combined means you have little reason to ever take it off, which is exactly as an activity tracker should be. The most important thing an activity tracker can do is to be invisibly present. You need to be able to keep it with you all the time and forget you’re even wearing it — meanwhile, it sucks up data about your life, delivers it to an application, and reports back with numbers and charts that are easy to understand. You want something that just melts into your life. After trying very many of these devices over the past several years, I’m convinced that always-on wearability is the most important thing. The Flex pulls that off better than anything that has come before.

It also has good ecosystem capabilities. If you own the Fitbit scale, it will use that device’s data to dynamically report back on your weight and percentage of body fat. If you are a MapMyRun (or Endomondo, Lose It, MyFitnessPal, etc.) user, it will import that data so it can get a better idea of things like calories burned, for example.

It also has tools to help promote weight loss. You can enter a goal and it will tell you how many calories you are allowed per day to get there, based on your activity. But this means manually entering the caloric values of your meals into its database, which is still sort of a chore. You have to be really dedicated to keep up with it.

Finally, the sleep tracking stuff is also quite good. When you go to bed at night, you either tap the device five times, or hit a button in the app to tell it you are going to sleep (and again when you wake). If you forget, you can manually input the hours that you slept. Either way, it will look at your movements to report back with how well you slept during the night. It also has a vibrating alarm to wake you, which is really great.

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FitBit Flex

(Photo: Mat Honan / Wired)

If you’ve been on the fence about which tracker to get, this is the one. It beats the Basis B1 which still doesn’t have a smartphone app and still requires a cabled connection to sync (although it does track heart rate, which the Flex does not). It beats the Jawbone Up, which now integrates with more third-party apps but doesn’t sync via Bluetooth and doesn’t have an app nearly as good as Fitbit’s. It beats the Withings, which looks really promising but at this point is still vaporware. It beats the BodyMedia Fit which tracks far more about you and even delivers prescriptive feedback, but despite a recent redesign, is still too big to be truly wearable. And it trounces the Nike+ FuelBand, which doesn’t track sleep, and has lots of accuracy problems.

This is the one you’ve been waiting for. And it was worth the wait. Go get it.

WIRED Great design. Best smartphone app of all the trackers on the market (Oh, and it’s on Android too). Amazing battery life. Scoble-proof: You can wear it in the shower.

TIRED Thanks for telling me what I’ve done, but please tell me more about what I should do. Would be nice if device itself showed number of steps taken at a glance.

Get your own: $100, 

More at WIRED:

12 Cell Phones That Changed Our World Forever

20 Gadgets Gifts Under $50

What Will Our Favorite Gadgets Look Like 10 Years From Now?

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