Apple rates the Watch Ultra 4 at up to 50 hours of normal use, which is the first time the Ultra has been quoted at two days without asking the wearer to switch anything off. For workouts, Apple quotes 18 hours with GPS and heart rate running and up to 45 hours in extended workout mode. The case is unchanged, in black and natural titanium, with new band colors and a titanium Hermes band. The Apple Watch Ultra 4 starts at $799, the same as the Ultra 3, and preorders opened on announcement day for a September 18 release.
What you are paying the same money for is inside. Ultra 4 shares the new Health Sensing system with the Series 12, so it inherits the rebuilt sensor and its much higher sampling rate, along with the Readiness score, which can change during the day as new data arrives rather than staying fixed at the morning reading. Audio Intelligence comes to the wrist too. For an Ultra 3 owner the case for upgrading is the battery and the sensor, because the watch on the outside is the one already on your wrist.