These models can measure distance using an accelerometer while linked with the GPS function of a smartphone via Bluetooth, and once you have taken measurements with a smartphone, the next time you will be able to measure distance with the watch alone. You can also check your activity history by linking with an app running on your smartphone. The app also helps to simplify the configuration of watch settings and training management. A Super Illuminator keeps face information easy to read, even in the dark, and the band’s soft urethane material improves the fit to the wrist, and vent holes improve breathability. This watch connects with your phone via Bluetooth to support auto time adjustment, phone notifications, step tracking, and other functions throughout the day. Battery life is approximately two years between replacements.