Specs: There are three collections: Apple Watch, Apple Watch Sport and Apple Watch Edition; the latter two are for the active customer and the luxury-minded one, respectively. The watch comes in two face sizes: 38 millimeters and 42 millimeters.
Functions: The Apple Watch works in conjunction with an iPhone and provides weather, stock quotes, upcoming calendar events, maps and other information. It can play music and send and receive messages; you'll feel a gentle tap on your wrist when you receive an incoming message. The watch has a retina display and comes with Apple Pay, the company's mobile payment system.
Price: Starts at $349, but higher-end models are expected to sell for thousands of dollars.
Personalization: Apple has been touting the vast customizable options available for the watch, including the screen interface, color and material of the band, the finish of the rectangular case and the kind of buckle.
Health monitoring: The watch will display the number of steps you take, calculate calories burned and measure the quality and frequency of activity. Over time, the watch will "learn" how you move and suggest daily fitness goals and encourage you to achieve them.
And here's what we expect Apple to divulge:
Full pricing: From the start, Apple has positioned the watch as a fashion piece. It has been featured in Vogue, and Cook has been clear that the device is as much about style as it is about tech. So be prepared for some luxury-level prices, particularly for the high-end 18-karat gold model, called the Edition. Tech and jewelry experts have predicted the Edition could go for at least $2,000, with the most elite configuration priced possibly as high as $10,000.
Pre-sale and in-store sale dates: Apple already said the watch would ship in April but hasn't given a specific date. As with the iPhone, expect the watch to hit store shelves on a Friday, with pre-sales to begin several days before.
Battery life: One of the big issues facing the Apple Watch is battery life. The company will almost certainly provide more details on how much juice you can get from the watch in both active and standby modes. There's also a rumored power reserve feature.
New app partnerships: A key part of the media event, held at the Yerba Buena Center for the Arts, will center on developer partnerships. Analysts say the watch needs to have a robust lineup of killer apps to lift the product into must-have territory. We've already seen a Starwood Hotels app, which enables Apple Watch wearers to use the device as the hotel room key. But Apple needs many more cool apps to persuade average consumers to buy.
Surprise features -- or other product announcements: Apple events are rarely limited to just one product, so there's a chance the company could release some updates to the MacBook line or possibly the iPad.