The main drawback to Fitbit's wearable activity monitors may be how unobtrusive they are. To hear users tell it, their trackers have taken more unplanned trips through the washing machine than a crumpled dollar bill.
Meet the new Flex, which for the first time puts Fitbit's technology into a wristband. Even simpler than the already uncomplicated clip-on versions, the band is also more powerful, and there's much less danger of forgetting it's there.
The $100 Flex joins an increasingly crowded field of devices jostling for wrist-share, including Jawbone's UP and the Nike+ Fuelband. But it's the best of the bunch.
The Flex package includes the wristband itself, a comfortably light, rubberized strap slightly thicker on one side, and the sensor, which lives in the band except when you pop it into its USB-powered charging bracket every five days or so.
If you have an iPhone or compatible Android phone, you'll most likely use Fitbit's excellent free app, available in the Apple App Store and from Google Play, to sync your data. (There's also a Bluetooth adapter for use with a personal computer.)
Wireless syncing is one of the Flex's big advantages over the UP, which requires you to remove a small, eminently losable tip in order to physically connect the band with your phone's audio port.
Another Flex advantage is that it makes a complete loop around your wrist, unlike the UP's overlapping ends, which get caught more easily on sleeves.
Then again, I had a devil of a time with the Flex's clasp, which holds it securely but requires a significant amount of fiddling and pressure to close properly. (The company says it's working on tweaking the design.)
Like its clip-on Fitbit siblings, the Flex is primarily focused on how many steps you take. The default goal is 10,000 a day, which experts say is a pretty good yardstick for moderate, healthy activity.
But unlike other Fitbits, as well as most other step counters, the Flex can recognize and give you credit for some nonwalking activities. In my case, the band recognized time I spent on a stationary bike and translated it into an equivalent number of steps to help me meet my daily goal.
That was a big deal for me, providing what felt like a much more accurate picture of my general activity.
The Flex is an almost 24-hour-a-day companion. At night, if you remember to tell it you're going to bed by tapping it, it tracks your sleep patterns. It also includes a silent alarm that vibrates to rouse you without bothering a still-snoozing partner.
It's sufficiently water-resistant that I wore it in the shower repeatedly with no ill effects, though the company does recommend removing it while swimming.
Unlike the Fuelband and Fitbit's other trackers, which can show letters and numbers, the Flex doesn't provide you with a lot of information at a glance. Its entire display, visible only when you tap it, consists of five tiny lights that illuminate based on how far you've progressed toward your daily goal; two lights, for instance, means you're 40 percent of the way there.
I missed being able to get more information directly from the Flex, but it wasn't far away. All I had to do was pull out my phone and access the app, which uses low-energy Bluetooth technology to minimize the battery drain.
More than just a display for the Flex, the app can be used to set goals and to log your food, water consumption, weight and activities the Flex can't track, such as yoga. And for a little mutual reinforcement, you can connect with friends to compare step totals.
More on wearable tech gadgets, including Google Glass.