While retaining the original iconic design, the fourth-generation Apple Watch has been refined, combining new hardware and software enhancements into a genuinely singular, unified form. The stunning display is over 30 percent larger and seamlessly integrates into the thinner, smaller case, while the new interface provides more information with richer detail. Apple Watch Series 4 with watchOS 5 brings advanced activity and communications features, along with revolutionary health capabilities, including a new accelerometer and gyroscope, which are able to detect hard falls, and an electrical heart rate sensor that can take an electrocardiogram (ECG) using the new ECG app,1 which has been granted a De Novo classification by the FDA.