Apple Inc. /zigman2/quotes/202934861/composite AAPL -3.17% kicked off its product launch event Tuesday with the announcement of its new Apple Watch Series 6 device. The watch comes with a blood-oxygen sensor that takes real-time readings in 15 seconds. The company announced that its always-on screen will be brighter than with previous models and it will allow users to see their altitude on the watch face. The device begins at $399 for a GPS-enabled model. Apple is also launching a new lower-cost model, called Apple Watch SE, which the company said will merge the design elements of its newest model with a more limited selection of apps. That model starts at $279 for a GPS-enabled version. The Apple Watch SE has a faster chip than the Apple Watch Series 3, which Apple will continue to sell for $199. The new models will be open for preorder today and will become available Friday. Apple is also rolling out a family-setup mode for cellular Apple Watches from Series 4 or later and it's meant to allow adults to manage Apple Watches for their children or older relatives. Prior Apple Watch iterations required an iPhone for pairing but people will be able to set up and manage Apple Watches for relatives with this new option even if those relatives down have their own iPhones. The company will add new watchbands as well, including those that slide on and don't require a clasp. Apple shares are up 1.2% in Tuesday afternoon trading. They've gained 36% over the past three months as the Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA -2.53% has risen 9%.