Fundamentally redesigned and re-engineered. The largest Apple Watch display yet. Electrical heart sensor. ECG on your wrist. Digital Crown with haptic feedback. Notifications for low and high heart rate and irregular rhythm. Fall detection and Emergency SOS. Breathe watch faces. Automatic workout detection. Yoga and hiking workouts. Advanced features for runners like cadence and pace alerts. Head-to-head competitions. Activity sharing with friends. Personalized coaching. Monthly challenges and achievement awards. Built-in cellular lets you use Walkie-Talkie, make phone calls, and send messages. Stream Apple Music and Apple Podcasts. And use Siri in more ways-even while you?re away from your phone. With Apple Watch Series 4, you can do it all with just your watch.