Apple Inc. uses extreme measures to keep its work secret, leading to many unanswered questions about its new smartwatch, set to go on sale sometime in April. Many of these questions may be answered in the company’s press event known as “Spring Forward,” which will be held tomorrow, Mar. 9. In the meantime, here are some things that are already known about the Apple Watch.

Three styles, two sizes, pricing starting at $349: the Watch (stainless steel), the Watch Sport, and the Edition (18-karat gold). The sport model is expected to start at $349, the stainless steel model between $499 and $549, and the gold model between $5,000 to $10,000. All three styles come in 38mm and 42mm sizes and have a variety interchangeable bands. They can be worn on either wrist.

Watch apps: some big companies, including Twitter, Facebook, Pinterest and Instagram, are planning to release apps for the Apple Watch at the time of its launch. United Airlines plans an app that will provide flight notifications. Starwood Hotels & Resorts Worldwide will have an app that can unlock hotel room doors. Some companies have been given special early access to the watch in order to fine-tune applications. Apple is attempting to build apps that are useful but not annoying, and are warning developers about constantly interrupting people with alerts that will drain the device’s battery.

Sales forecasts: Research analysts expect total Apple Watch sales in 2015 to be between 8 million and 30 million. Katy Huberty, a Morgan Stanley analyst, says that initial demand could be stronger than the iPad and the iPhone at the time they launched. The watch is Apple’s first new device since 2010, which is when the iPad was introduced, and the stakes are high. Optimism toward new products from Apple Inc., including the Watch, have already sent company shares to record highs. Huberty estimates that Apple may ship as many as 30 million watches in the first 12 months.

Battery life: more is actually not known than known, although Apple CEO Tim Cook said he expects the battery in the Apple Watch to last all day. With constant active use it may only last about 2.5 hours. Combined active and passive use will probably allow about 19 hours of battery life. A “power reserve” feature may allow the watch to function with all features except timekeeping disabled in order to reduce power consumption. Apple is suggesting that developers design their apps to be used to only 10 seconds at a time to save battery life.

Health and fitness: many health features will be included with the watch at the time of launch. This includes a built-in heart-rate sensor. The device can also track various types of daily activity, movement and exercise. It can be set to provide a gentle vibration to remind a user to get up and move if they have been still for too long.

Communicating: The Apple Watch pairs with an iPhone, and displays notifications from both. Messages, emails and calls can be transferred from the Watch to an iPhone for longer activity in order to save the watch battery. Some developers have noticed problems, such as slowness, with the function of the Bluetooth connection between the phone and the watch, creating a lag time for some applications.

The watch’s final release date is expected to be announced on Monday during Spring Forward. The press event is being held at San Francisco’s Yerba Buena Center for the Arts, and will be live streamed.