We're covering Apple's iPhone X event in Cupertino this morning, and the first major product announcement is the Apple Watch Series 3. Apple's COO Jeff Williams has taken the stage to announce the third generation of Apple's wearable. Its has built-in cellular support (well there is cellular and non-cellular models), a 70% faster dual core processor, and it's 50% more power efficient.

Williams demonstrated the Watch's cellular capabilities on-stage by calling Deirdre Caldbeck of the Apple Watch team from his Series 3 Watch (sans iPhone), using AT&T. Caldbeck was shown on video, paddle-surfing in the ocean, and it actually made for a really impressive live demo. The call connected quickly, and the audio quality was surprisingly clear given the conditions.

Here's more from Apple on cellular:

Apple Watch Series 3 (GPS + Cellular) features a full LTE and UMTS cellular radio that switches seamlessly to cellular when it is away from iPhone. The watch shares the same number as iPhone so there’s no need to provide an additional number to family, friends or colleagues; and to help get customers started, participating carriers are also offering special introductory cellular plans at launch. Customers have the ability to make cellular calls directly with Apple Watch Series 3 (GPS + Cellular) and, when paired with AirPods, enjoy a seamless and fully wireless experience. Apple also pioneered an industry-first antenna design that uses the display itself as both a transmitting and receiving element for LTE and UMTS, while introducing a built-in eSIM that is over one-hundredth the size of a traditional SIM card, making over-the-air activation possible without compromising space.

Apple says that the Watch will also be capable of streaming Apple Music without an iPhone, although it doesn't sound like this feature will be ready at launch time.

Powering the Apple Watch Series 3 is Apple's S3 chip. It features a faster dual-core processor, which allows for quicker app launch times and smoother graphics, and, for the first time, enables Siri to speak using the built-in speaker. It also features a new W2 wireless chip with 85% faster Wi-Fi and Bluetooth, and better power efficiency, and a barometric altimeter that assists with tracking activities, elevation gained, stairs climbed, and more.

Apple Watch Series 3 is the same size as its predecessor (Apple does say, however, that they extended the crystal that encases the heart rate monitor by two sheets of paper) and comes in a host of new case and band colors/designs. It will be available for pre-order on September 15, and start shipping on the 22nd, starting at $329. Apple also notes that carriers will be offering special introductory cellular plan pricing.