Fitbit Flex Wireless Sleep + Activity Tracker Wristband

Editor rating

4.1/5 on 02/05/2015

User's rating

10,542 reviews


  • Tracks steps, distance, calories burned and active minutes
  • Monitor how long and well you sleep
  • Wakes you (and not your partner) with a silent wake alarm
  • LED lights show how your day is stacking up against your goal
  • Slim, comfortable and easy to wear (sold with both large and small wristbands included)
  • Includes small and large wristbands


  • No display

Fitbit Flex

Fitbit Flex is an advanced activity bracelet (Last year’s Christmas gift 2014) from Fitbit and come in many different colors. Fitbit Flex has a built-in 3-axis accelerometer that senses your movement patterns and measures the calories burnt, distance traveled, number of steps and sleep quality. In addition, Flex track of  active minutes and the  number of hours you sleep. You can put target activity and follows simple where you stand by the 5 LEDs that glow depending on how close your goal you are. A brilliant light indicates 20 percent of the target. Fitbit Flex also has a built-in vibrating, “Silent Alarm” and is waterproof down to 10 meters. It comes with two bracelets in two sizes (large and small) so you can use what suits you best.

Free membership at – with the ability to log and track activity, food, sleep, water, BMI, weight, etc.


Facts about Fitbit Flex:

  • Size of the bracelets: Large (161-209 mm) and Small (140-176 mm). The numbers indicate the circumference of your wrist. Both sizes included in the box.
  • Battery: Lithium-polymer that holds about 5 days when fully charged. Should be recharged every 3rd to 5th day for optimal tracking.• Fungear in the range of -20 ° C to 45 ° C and up to 9144 meters altitude
  • Waterproof up to 10 meters
  • PC / MAC requirements: Windows XP / Vista / 7/8 or Mac OS X 10.5+, USB port, Internet
  • Browser: Chrome 12 or higher, Firefox 3.6.18 or later, Internet Explorer 8 or higher, Safari 5.0.5 or later
  • Memory: Recommend that you sync issues your Fitbit Flex often, but it can store up to 7 days with detailed data (minute by minute) as long as there is power in the battery. It also keeps track of the last 30 days but then stores the total number of steps per day, total distance per day and the total calories per day.
  • Syncronizes automatically all the data for PC / Mac when it is within approximately 6 feet from the USB adapter (supplied) connected to the computer.
  • To sync to smartphone or tablet / e-reader required Bluetooth 4.0 / Bluetooth Smart.  There are currently including  the iPhone 6 Plus / 6 / 5s / 5c / 5 / 4s, iPad Air / Mini / 4/3, iPod Touch ( 5th gen.), Samsung Galaxy S5 / S4 / S3, Samsung Galaxy Note II / III / 10.1 and many other devices. Here you can see if your device can sync wirelessly with Fitbit Flex:
  • Included: 1 Fitbit Flex Tracker, two bracelets (large and small), 1 wireless Bluetooth 4.0 USB Dongle, 1 charging cable, free membership at and access to mobile apps for iPhone and Android.
  • Fitbit uploader application is required and can be downloaded free.