Fitbit Surge

Ffitbit Surge is a $249 all-day activity tracker with a built-in optical heart rate monitor.

The optical heart rate monitor on the Fitbit Surge looks like two glowing green lights on the back. It reads heart rate continuously.

The face of the watch changes when you do activities. For example, this screen shows a lap run in progress. You can customize the bottom data point, which is currently showing heart rate.

The Fitbit Surge has a customizable face so you can change the look of the clock.

Many of the customizations that you can make to the Fitbit Surge have to be done in the companion mobile app or Web app, such as selecting the clock interface you want to see on your home screen.

When you wear the Fitbit Surge during an activity, it tracks your heart rate and displays it on a graph, like this one, so you can see the different heart rate zones you were in and for how long.

Fitbit Surge estimates how many calories you burn, and it can do so more accurately than other devices because it has heart rate data informing it. This screen shows the estimation for calories burned per minute during a workout.

You can customize the Fitbit Surge so that activities you do regularly show up in a list right on the watch so you can select them before you start. The watch then records your time and activity for that session and estimates the calorie burn based on the activity selected.

For runs, walks, and hikes, Fitbit Surge has GPS, so it can map your route, track your pace, and more accurately measure your distance.

The Fitbit Surge taps into the same familiar Fitbit app interface as other Fitbit devices. When you connect a Surge or Charge HR, however, a new line for heart rate shows up on your homescreen.

The more you use your Surge to track runs, yoga sessions, and other workouts, the more you'll see your calendar filling up with activity.