The Flex’s strap design makes it light and comfortable to wear. It also offers handy Bluetooth syncing, and Fitbit’s platform gives plenty ways to analyze your stats. While the Flex isn’t without some flaws, the gadget is the most complete product of its kind you can buy. It can track steps taken, sleep quality, and it syncs data wirelessly with PCs and Macs automatically. Comfortable to wear, the Flex can communicate directly with iPhones and select Android smartphones, and is water-resistant as well. After all, the device lacks a real screen capable of displaying alphanumeric characters. Instead the Flex sports a thin sliver of a display cut from smoky dark plastic. Underneath the plastic sits a row of five tiny, white LEDs that blink to indicate the Flex’s status. The device is fully water-resistant and is designed to shrug off exposure to splashes and short immersions in liquid. The device calculates this by factoring in your age, height, and weight, which you punch into a linked Fitbit account online. My experience mirrored these claims and was able to last approximately 5 days without needing to recharge. By contrast, the Flex is comfortable to wear and has more features, including Bluetooth syncing ( iOS and Android) and access to powerful analytical tools. Fitbit flex is also a compelling budget choice.