If you're considering upgrading your Fitbit Flex, then you owe it to yourself to check out the updated Fitbit Force ($130), the company's newest wearable activity tracker. While it still contains most of the features of the earlier model — you wear it on your wrist, it tracks your steps, the distance you've traveled, the calories you've burned, your minutes of activity, and the quality of your sleep — it also adds a couple of key features. It has an improved blue OLED screen letting you read the display more easily, as well as an altimeter, adding floors climbed to the data it tracks. It also features a clock, and a stopwatch, as well as the ability to sync with your phone automatically over Bluetooth.