The GPS model allows you to make calls and answer texts from your wrist Large OLED Retina display Up to 2x faster processor than Series 3 Track your daily activity on your Apple Watch and see your trends in the Fitness app on iPhone Measure exercises like running, walking, cycling, yoga, swimming and dancing Waterproof design Check your heart rate at any time with the heart rate app Get notifications for high and low heart rates Sync your favorite music and podcasts Built-in compass and real-time altitude readings It can detect if you have had a hard fall, then automatically call emergency services for you SOS Emergency Service allows you to get help from your wrist watchOS 7 with sleep tracking and new customizable watch faces