Apple has unveiled the Apple Watch Ultra 4 at its "Surprise and shine" event, a rugged smartwatch that looks nearly identical to last year's Ultra 3 but gains a new S11 processor to support the smarter, AI-powered Siri assistant coming with watchOS 27. The upgrade matters because it brings meaningful health-tracking and battery improvements while positioning the device to handle Apple's more capable on-device AI features, including a new "Recaps" tool that uses the watch's microphone to summarise the wearer's day.

The Ultra 4 has improved ECG electrodes and more efficient green LEDs, enabling heart rate readings every five seconds and heart rate variability checks every five minutes. Battery life rises to up to 50 hours of normal use, 84 hours in Low Power Mode, and up to 45 hours during extended outdoor workouts. It's available for preorder now in the US, UK, Canada and over 50 other countries, with shop availability from 18 September, starting at $799; a premium Apple Watch Hermès Ultra 4 with a titanium finish and exclusive bands and watch faces is also being introduced.