Bigger Apple Watch screenThe displays are bigger and attractive.
The larger model now comes with a 45mm screen, up from 42mm, and the smaller version's previously 38mm screen is now 40mm. However, watch bands for previous models will still work with Series 4.
Heartbeat reading can show your heart rate to your doctor to help detect any abnormality.
The feature "is really a game changer as the first wearable device with this feature", Evercore ISI analyst Ross Muken wrote in a note to investors.
"Apple Watch has become an intelligent guardian for your health", said Apple CEO Tim Cook.
The third feature is made possible by the electrocardiogram on the back.
Theirs is the first electrocardiogram ever to be available over-the-counter, Apple's COO Jeff Williams said. After about 30 seconds, the device measures heart rhythms, classifies them, and alerts the user if there are signs of atrial fibrillation.
"This device is packed with features which not only bring notifications to your wrist but also keeps an eye on your health and even lets you pay for your weekly shop via Apple Pay". Thee user places a finger on the Watch's digital crown, so that a tiny electrical signal can be sent through the body by one sensor and received and measured by the other. The Digital Crown now has haptic feedback to give a more clicky feel, and the microphone has been moved to the opposite side of the speaker to prevent echo. Radio waves can pass through the front and the back, which means better reception. This allows signals to pass from the front and the back to improve Global Positioning System and LTE.
The Series 4 has the same 18-hour battery life as the Series 3, Apple says. If you want cellular connectivity, you will add $100 to the price point. The complications have been enhanced to be more precise and informative.
The first new item on the agenda for tonight's Apple event was the Apple Watch. The watch face has been redesigned too, with eight customisable areas. Each one can be completely customized so you can focus on productivity, friends or health.
Saying that, many apps used a black background already so it was quite hard to see the border, but with the larger screen you can see so much more information. You can glance at your fitness progress, calendar or flight plans. The new Watch also has a better speaker and mic compared to Watch 3. The display panel itself is a low-temperature polycrystalline oxide (LTPO) OLED affair that Apple says is good for improved power efficiency.
Apple Watch Series 4 runs watchOS 5. The Series 4 also has a next-gen accelerometer and gyroscope with up to 2x dynamic range and up to 32 g-forces. Pricing starts at $399 for the Wi-Fi-only version, and $499 for the cellular edition. It will be available for pre-order starting this Friday and will be widely available on September 17th.