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Fitbit Flex 2 Review


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  • Sleeker design
  • Comfortable to wear
  • Waterproof
  • Long battery life


  • Basic exercise tracking
  • Basic notifications can be improved
  • Fiddly clasp

Key Specifications

  • Review Price: £79.99
  • New, slicker design
  • Waterproof to 50m with lap counting
  • All-day activity and sleep tracking
  • Interchangeable bands and accessories
  • Automatic exercise recognition
  • Smartphone notifications

What is the Fitbit Flex 2?

The original Fitbit Flex sat at the entry-level end of Fitbit’s product range. It was a relatively discreet tracker that did the basics of activity and sleep tracking, but offered little beyond that.

For its update, which was released alongside the new Charge 2, Fitbit has brought the Flex more up-to-date, adding waterproofing and some rudimentary smartphone notifications. You’re also able to dress the Flex 2 up and down with customisable accessories. However, even with these upgrades, there are still better-value fitness trackers out there.

Watch: Wearables and fitness buying guide

Related: Best Fitness Tracker

Fitbit Flex 2 – Design and Setup

The actual tracker component of the Flex 2 is 30% smaller than the old model. As before, it slips into an included standard elastomer band if you opt for the basic version, which I was sent for review. The band is narrower than the old Flex, and is now as wide as the Jawbone UP3. It contours to your wrist more snuggly, however, thanks to the use of more supple materials.

The Flex 2 is available with bands in a range of colours, including black, lavender, magenta and navy, so you’ll easily be able to find one to your taste. In addition, the band now features a textured pattern, which makes it less plain than it would otherwise be, but it doesn’t feel coarse against your skin.

You’re supplied with two different-sized bands as standard. Additional classic bands minus the tracker are available in a larger variety of colours. There are far fancier options available, too, which I’ll come to later.

Related: Best Fitbit

Fitbit Flex 2 3

The Flex 2 still uses a button clasp for securing itself around your wrist, which is just as fiddly to use as it’s proved before. I gave the original Flex to my mum, who always struggled to put it back on her wrist without assistance, so I ended up having to buy her a third-party strap that used a watch buckle instead. She would struggle in the same way with the newer model.

Fitbit Flex 2

Part of the issue is that there’s no loop through which to thread the strap, meaning you have to line up the buttons with the holes; it’s trickier than you might think especially for anyone with restricted motor control. I wish Fitbit had just used a watch buckle as is used on the Charge 2.

Related: Fitbit Ionic review

Fitbit Flex 2

There are other strap options available from Fitbit, however. Taking a page out of Misfit’s book, the Flex 2 can now be dressed up much more like an item of jewellery, which is great for anyone looking for a more discreet tracker.

Related: Misfit Ray review

There’s a range of bangles available in silver, gold and rose gold that look, to my eyes at least, quite classy. Jewellery is always a very personal thing, though. At £69.99 without the tracker for the silver model, or £79.99 for the others, they’re not cheap. There are also collaborations with fashion houses such as Public School and Tory Burch, which bring even more flare to your wrist.

Fitbit Flex 2 5

You’re not limited to wearing the Flex 2 only on your wrist, though. There’s also a pendant accessory for the same price if you’d rather wear it around your neck. However, you’ll lose sleep-tracking and Fitbit’s SmartTrack functionality if worn this way.

The latter is Fitbit’s ability to automatically detect activities such as running or swimming. Still, if you keep your standard bands for actual activities, the pendant is a nice way to be able to still wear the Flex 2 when it might look out of place on your wrist.

The other big improvement from the original Flex is the positioning of the progress LEDs, which are now vertical and much easier to see at a glance.

As usual, the Flex 2 pairs with a companion app for Android and iOS and connects over Bluetooth. You’ll probably be prompted to update its software once you pair, but this doesn’t take very long. Then it’s simply a matter of setting up a profile if you don’t already have one. This is where you can set your various goals.

After this, all of your activity will sync with the app so you can keep track of it all from the dashboard.

Related: Best Smartwatch

Fitbit Flex 2

The app will also let you customise what notifications are relayed to the Flex 2. Your options are limited, especially considering you have only that row of LEDs. You can have the Flex 2 vibrate when a message comes through and this extends beyond just SMS. I had mine buzz whenever I received a WhatsApp message, but it also works with Facebook Messenger. As well as vibrating, the top and bottom LEDs on the Flex 2 will light up in white and blue shades.

For incoming calls, the Flex 2 band will vibrate and the LEDs will light up one after the other in a wave pattern. The notification system here, while very basic, does well enough with what’s available – but there’s definitely potential for better customisation, which will supposedly arrive at a later date. It would be useful to be able to customise how the LEDs light up so you know if one of your favourite callers is ringing, for example.

Fitbit Flex 2
Synchronised swimming stars Aquabatix put the Fitbit Flex 2 through its paces underwater

Fitbit Flex 2 – Activity Tracking and App

Once you have the Flex 2 wrapped around your wrist, its strength lies in the fact that you can largely forget about it. All of your steps are automatically counted and your forty winks all add up when you sleep.

The previously mentioned SmartTrack will kick in during certain exercises such as longer-duration walks, running, cycling and now, swimming. You can configure when SmartTrack starts through the app, but the settings are a little tucked away for my liking.

Fitbit Flex 2

You’ll also need to turn on the swim tracking; this is disabled out of the box. Fitbit says this is to conserve battery life for non-swimmers, which is fair enough. Once you turn it on, you’ll need to also set the pool length if you want the lap counting to be accurate.

Even then, when I went for a test swim its lap counting was considerably off the pace, especially compared to the excellent – and, admittedly, far more expensive – Apple Watch Series 2.

In fairness, this can be attributed to my rather haphazard, stop-start style of swimming, which throws off the tracking. If you’re a stronger swimmer, less prone to stopping or flailing, you’ll likely find the lap counting much better as was the case when I gave the Flex 2 to my other half. The Flex 2 is able to detect four different swimming strokes.

Related: Workout logs are the key to getting fitter – here’s why

Even if you’re not a swimmer, the waterproofing – which is a first for Fitbit – is useful just for the mere fact that you don’t need to take off the Flex 2 to shower. I’ve always said that every time you take an activity tracker off is another opportunity for you to not put it back on, which defeats all the benefits of having one.

Fitbit Flex 2

For running, there’s no GPS as you’d expect, but there’s also no Connected GPS mode either, which was available on the Fitbit Charge 2. This let the Charge 2 piggyback the GPS of your paired smartphone, even if the run was triggered automatically through SmartTrack or manually on the band.

The actual duration of an automatically tracked run is accurate, but you don’t get any other metrics alongside. The synchronised data just amounts to a calories-burned graph and the impact on your day. The Fitbit app doesn’t even show the distance calculated by the Flex 2’s accelerometer, which the Charge 2 was able to do even when not using Connected GPS. It makes the exercise tracking feel rather bare bones.

As for the step counting, the Flex 2 was pretty close to the Fitbit Charge 2 and Jawbone UP3 that I was wearing concurrently. They’re all going to deviate slightly due to different algorithms, so it’s the consistency that’s most important.

As before, you can give the Flex 2 tracker a quick double-tap and the LEDs will light up to show your progress towards your daily goal, with each LED representing 20%. It’s a progress update that’s easy to understand and makes you want to “fill the bar” when you know you’re a little short at the end of the day. The tracker will vibrate in celebration at being fed enough steps.

The Flex 2 still lacks an altimeter, which is a shame. Measuring floors climbed is a good motivator to take the stairs instead of the lift and is an easy way to incorporate a little extra cardiovascular exercise throughout your day.

You can also set move alerts in the Fitbit app, to tell you to stand up and try to get at least 250 steps every hour. You’ll feel a vibration from the band as a reminder. Other prompts to stay mobile include “Active Minutes”, which are periods of moderate activity in excess of 10 minutes.

The dashboard will show how many you’ve accumulated and you can see your performance graphed day-by-day. It’s a good incentive to get moving – if you remember to keep an eye on it.

Fitbit Flex 2

Challenges make a return, which I enjoyed from the Charge 2. These take you on virtual guided tours of famous landmarks, where each step you take in the real world progresses you virtually. You’ll pick up facts and trivia about the location as you go, along with health and fitness advice. As promised, the New York City Marathon was just added and more are coming. Otherwise, you can take part in leaderboard challenges with your friends if a bit of friendly competition is needed to get you motivated.

The Fitbit companion app is also being updated with a new community tab, giving an even bigger push to the social elements of fitness through new sections. You’ll be able to connect with friends and family as you would expect, and share inspirational moments and compare progress. You’ll also be able to tailor you personal goal, and identify your focus areas such as steps or getting better sleep.

You can complete a survey to help identify your motivation and then get personalised recommendations based on your objectives and historical data captured by your Fitbit. You’ll also be able to find like-minded people in the Groups section relating to topics such as wellness, weight loss, fitness and nutrition. Fitbit will also be curating content written by health and fitness experts.

Sleep tracking was as as good as I saw on the Charge 2. I’ve always been fond of Fitbit’s more useful analysis of sleep, which provides a Time Asleep duration, rather than general sleep duration. This deducts the time you spent restless or awake, offering a better indication of your actual sleep quality.

Fitbit Flex 2

Still, a bit of guidance on how to improve your actual sleep quality from the app wouldn’t be amiss. In this regard, I’ve always been fond of Jawbone’s Smart Coach, which pops up with useful tidbits of guidance.

Related: Best mattress

Fitbit Flex 2 – Battery Life and Charging

While I was happy to discover that you no longer need to take off the Flex 2 to shower, the fact the device doesn’t need to be charged regularly was also a huge bonus.

I receive a lot of WhatsApp notifications throughout the day (I’m very popular, obviously), which meant the Flex 2 was buzzing constantly. Even then I managed to last around five days before needing to give it a top up; you can stretch this out if you’re more restrictive with the notifications.

Topping up the power is simply a matter of removing the tracker from whatever strap or accessory you’re using, and placing it into its USB charging cradle. Annoyingly, though, charging is very slow – which is a little odd for such a basic device. I tend to charge the Flex 2 while I’m sat at my desk; otherwise, I feel like I’m losing precious steps towards my daily goal and charging overnight means missing out on sleep tracking.

Should I buy the Fitbit Flex 2?

Fitbit Flex 2

The Flex 2 is a decent improvement over the original Flex, with the addition of waterproofing making it a much easier device to live with – even if you’re not a regular swimmer. Not having to take it off to shower is a convenience you shouldn’t overlook. The added notifications are a good addition, too, but could certainly be more refined.

However, the Flex 2 is still a rather basic activity tracker for the money. The design is improved, but its standard elastomer band isn’t the most stylish-looking out there. The fancier accessories are rather pricey when added to the cost of the tracker.

For me, the Moov Now is still the activity tracker to beat. It offers far more elaborate exercise tracking and the same great waterproofing for less money.


The Fitbit Flex 2 is a solid upgrade over the original, but it’s still a rather basic activity tracker for the money.

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