Apple announced the next version of the rugged and durable Apple Watch Ultra at today’s “Surprise and shine” event.

The new model follows the Apple Watch Ultra 3, which launched last year. That watch debuted with upgrades including improved battery life, support for 5G networks on the cellular model, satellite-based messaging and emergency calling, and a slightly larger display thanks to a slimmed bezel.

The Apple Watch Ultra 4 features an improved sensor with upgraded electrodes for better ECG measurements alongside more power-efficient green LEDs allowing for more accurate heart rate measurements all day long and during physical activities. The improved energy efficiency allows the Ultra 4 to take heart rate readings up to 60 times more frequently than previous models at 5-second intervals. Heart rate variability measurements, a metric that provides insights about how your body responds to stress and recovery, can now be taken every five minutes.

At Apple’s annual WWDC conference earlier this year, the company introduced its smarter and more capable Siri AI assistant that will be coming to the newest Ultra models as part of its upcoming watchOS 27 release. The update will also include a redesigned app grid, improvements to health and fitness tracking, and battery life optimizations.