Inside the Charge 3 are an accelerometer, gyroscope, optical heart rate monitor, and an SpO2 sensor for tracking blood oxygen levels. The Charge 3 is the third Fitbit device to include an SpO2 sensor, following in the footsteps of both the Fitbit Ionic and the Versa smartwatches. However, currently the SpO2 monitor lies dormant inside all of these devices as Fitbit hasn't made use of it yet.
If you don’t need your smartwatch to look business-casual, you want more fitness and exercise features than our top pick, or you’re a Samsung loyalist, the Samsung Gear Sport is a better pick for you. (You can use the Gear Sport with non-Samsung phones, but doing so requires that you install at least four apps.) The Gear Sport handles all the casual notification and message-triage functions of a smartwatch about as well as our top pick—with the exception of voice transcription—but it adds heart-rate monitoring, GPS tracking, swim tracking, and built-in reminders to move throughout the day. It doesn’t do all of these things perfectly, but it does just enough to make for a generally useful smartwatch, with great battery life and a clever interface.
It's also very bulky. Sitting at 46mm wide might not sound like much, but then you have the depth, and there's a lot of it here. In fact, if we had to pick one criticism of the Watch Sport it's that it crams so much in, it does so to its detriment. The size will be too overbearing for many, but the pay-off in size means that most of the great features of the Watch Sport have been discarded.
Tizen is a Linux-based operating system for devices, including smartphones/tablets, in-vehicle infotainment (IVI) devices, smart TVs, laptops/desktops and other platforms. Tizen is a project within the Linux Foundation and is governed by a Technical Steering Group (TSG) composed of Samsung and Intel among others. Samsung released the Samsung Gear 2, Gear 2 Neo, Samsung Gear S, Samsung Gear S2 and Samsung Gear S3 running Tizen.
What’s on display?: Most smartwatches have full-colour displays, though the underlying technology will determine how good the screen looks. There has been a move towards AMOLED (active matrix organic light emitting diode) displays, as used in the Apple Watch which present a bright screen, crisp text and accurate colours. Fitness trackers tend to have lower-quality screens and may not present in full-colour, partly to save battery life.
Fitbit's Versa is a sleek, stylish smartwatch that works with both iOS and Android and costs less than $200, which makes it the best value smartwatch you can buy. The watch lasts four days on a charge, offers female health-tracking, advanced sleep-tracking and an app store with popular apps such as Starbucks and Pandora. You can even store music offline to listen to while you work out.