Source: Apple.At today’s Surprise and Shine event, Apple introduced the new Apple Watch Series 12 and Apple Watch Ultra 4. Both models build on the devices’ existing designs, adding new health and fitness features as well as what Apple calls Audio Intelligence. The star of the Apple Watch show that powers those features on both models is the brand-new S11 chip. Let’s dig into the details of what the new chip and improved sensors means to both models.Apple Watch Series 12The Series 12 takes a heart reat measurement every five seconds. Source: Apple.The new Apple Watch Series 12 comes in 42 and 46mm sizes and is equipped with the new S11 chip. Apple says that enables the device to take sixty times the heart rate measurements and 24x HRV readings compared to the Series 11 Watch. More heart rate measurements and HRV readings mean more accurate and meaningful readings; in fact, better than any other wearable on the market, according to Apple. Apple says step tracking is more accurate, too.The Series 12 has improved sensors, too. There’s a larger, more power-efficient green LED array for measuring your heart rate every five seconds and a Secure Enclave for processing audio privately and securely. On the outside, the Series 12 features Ceramic Shield 2, making it tougher than the Series 11. The case is now IP6X rated for dust and can be used to six meters of depth. Plus, the battery is rated to last 24 hours during normal use and a 15-minute charge will power it sufficiently to last 12 hours.Improved sensors. Source: Apple.HRV readings have been added to your overnight vitals statistics to provide a more complete picture of your health, and Apple has added daytime vitals which you can track during the day. The new health sensing features also enable Readiness, a daily score that uses your vitals to give you a sense of whether your body is ready for a big workout or whether you should take it easy.The Series 12 comes in a wide array of finishes, too, including aluminum, titanium, and ceramic. The aluminum model comes in Dark Bronze, Light Gold, Black, and Space Gray. Titanium is polished and comes in Radiant Gold and Natural. Finally, Ceramic comes in Pearl White and Night Blue. Aluminum models start at $399, titanium at $699, and ceramic at $899. It’s great to see so many different choices and styles. We’ll have a separate story that covers Apple Watch bands and other accessories on the site soon.Siri Recap, which is coming later this year. Source: Apple.With the richer data delivered by the S11 chip that powers Apple’s new Health Sensing System, the company revealed a wide variety of new software features, including:Live Rewind, which with a double press of the Digital Crown displays a transcript of the last 15 seconds of a conversation, allowing you to see what was spoken as text. The feature plays a chime and shows an animation when it’s activated.Siri Recap, which can be activated at all times, on a schedule, or on demand via Control Center and produces a summary of conversations.Sound recognition using on-device intelligence to detect alarms, a baby crying, sirens, and other sounds.Automatic song detection with Shazam.It’s worth noting that Siri Recap and Live Rewind won’t be available until later this year.The Series 12 looks to be a big step forward for the Apple Watch. Some years in the past have been hardware-focused, while others have leaned into new watchOS features. This year, users get both in what appear to be meaningful measures, which is great.Apple Watch Ultra 4Source: Apple.Personally, I’m even more excited for the Apple Watch Ultra 4, which starts at $799. I love its battery life, which is getting even better this year, as well as the fitness features. The Ultra 4’s color options are far more limited than finishes available with the Series 12, with options for natural and black titanium. I realize the Ultra is a more utilitarian watch than the Series 12, but I still wish Apple would expand their case and band choices a little more.That said, there are a lot of other features to like in the latest model. The battery life is now rated at 50 hours up from 45, and the Ultra benefits from the same chip and sensor improvements found in the Series 12. Plus, in Low Power mode, the Ultra 4 can last for as much as 84 hours, which is truly impressive. Fast charging enables 18 hours of battery life, which is something I know I’ll appreciate when I’m ready to run and find my watch battery nearly spent. The Extended Workout mode for runs, hikes, and walks can last for up to 45 hours, too.Source: Apple.Like the Series 12, the Ultra 4 incorporates the S11 chip and new sensors. That enables Readiness on the Ultra 4 and more meaningful heart rate and HRV readings. Audio Intelligence is part of the Ultra 4’s software story, too, with Live Rewind, Siri Recap, sound recognition, and automated Shazam results available too. So, as with past Ultra models, the big difference between the Ultra 4 and the Series 12 is the display size and battery life, which I expect will come in handy with the watch’s new capabilities.HealthThe Health app will be updated later this year.Finally, the iPhone’s Health app is being updated with a new design and incorporates the enhanced data collected by the new Apple Watch models. There will be a new Insights tab that provides health information based on the data stored in the app. Plus, Health will include a Longevity tab for longitudinal health data and a Health age calculation to give users a sense of their health relative to their age. It’s worth noting that the updated Health app, like Siri Recap and Live Rewind, won’t debut until later this year.This is the first year in a long while that i’ve been excited about new Apple Watches. I’d convinced myself that this year would amount to small, incremental changes that wouldn’t justify an update for another year or two Instead, I immediately ordered the Apple Watch Ultra 4. I love the combination of more and better health readings, Readiness, and the new Health app, and I’m intrigued by what I can get out of Audio Intelligence in my day-to-day life. I’ll know soon enough I guess because mine arrives next Friday.You can follow all of our September 2026 Apple event coverage through our September 2026 Apple Event hub or subscribe to the dedicated September 2026 Apple event RSS feed.