Apple Watch Series 12 and Apple Watch Ultra 4 are official. Apple has announced its two new Apple Watch models as part of its product event today. An upgraded health tracking system is key to both models.

While both new models feature a familiar design, an upgraded heart rate monitor is key to the new health sensing system.

For example, the new system now measures heart rate data every five seconds, a 60x frequency increase over previous models.

Apple is also measuring HRV every five minutes. The new system is called the most accurate heart rate sensor in a wearable, according to Apple.

Apple is also introducing a new readiness feature. This is based on activity, vitals, and sleep data.

Readiness is a new feature based on activity, vitals, and sleep data

Additionally, Apple is adding a new Audio Intelligence feature to Apple Watch Series 12 and Ultra 4.

This includes sound recognition, like doorbells. There’s also a “live rewind” feature that lets you go back 15 seconds to transcribe what someone just said. It’s invoked by double-clicking the Digital Crown, which used to be multitasking.

Apple has published a new support document that details what audio intelligence does and how it works.

Siri recaps is another new feature. When enabled, it can summarize things like meetings, based on audio notes. Apple Watch also gains a new Siri Modular face as part of the new system.

Apple Watch Series 12 and Ultra 4 run on Apple’s new S11 chip. It includes A20 Pro-derived CPU, GPU, and Neural Engine components.

Colors include space gray, black, light gold, and bronze aluminum. Ceramic Shield 2 protects the front glass.

Radiant gold and natural make up the polished titanium finishes. Ceramic returns in pearl white and a new dark blue option. Hermes adds gold to the lineup.

Apple Watch Ultra 4 includes a larger battery with over two days of battery life. Black and natural titanium remain the two finish options. There’s also a new titanium band.

Apple Watch Series 12 and Ultra 4 are available for pre-order from today. Both launch on September 18. Pricing remains the same as the Series 11 and Ultra 3, from $399 and $799, respectively.

Here’s the official Apple Watch Series 12 press release. Apple Watch Ultra 4 has its own press release as well.

Catch up on all the Apple news around today’s event here.