Fitbit Alta HR Activity Tracker in black. This sleek device utilizes PurePulse technology to accurately track your heart rate data from your wrist. The Alta HR also counts how many steps you take, how far you walk, how many floors you climb, the number of calories you burn, and the time you spend active. It connects to your smartphone via Bluetooth and syncs its data wirelessly while providing you with notifications, workout assistance, and more on its OLED display. The Alta HR is also water-resistant, which means you can wear it out in the elements. Its rechargeable battery lasts up to seven days on a single charge, so you can wear it more and charge it less. It comes with a large-sized band, which is designed to fit individuals with wrists measuring 6.7 to 8.1″ around. The band can also be swapped out for other colors, sizes, and materials.