Apple has revealed Apple Watch Series 6, which adds a new blood oxygen saturation sensor. Blood oxygen is an important vital sign that can drop to dangerous levels in those with COVID-19. Apple has started three research studies that use the new sensor, including one focused on COVID-19 and the flu. The other studies are focused on asthma and heart failure. The Watch can measure blood oxygen periodically in the background, or on demand in 15 seconds. Series 6 also uses a new S6 processor, has a display that's 2.5 times brighter in always-on mode, and has an always-on altimeter. Apple also announced new family features designed to make Apple Watch better-suited for kids and seniors. Family Setup lets you use your iPhone to set up someone else's cellular Watch, such as your phone-free kid. It also lets you control the contacts your kid can communicate with, and set up location alerts. A School Time mode restricts functions to help kids focus during school hours. Series 6 is available in new color options, including a blue or red aluminum body. New band options include "Solo Loop", a single fixed band without a clasp, available in nine sizes. Solo Loop is available in a variety of colors, and either solid silicone or a woven design made with silicone yarn. To reduce electronic waste, Series 6 does not come with a USB power adapter. Apple Watch Series 6 is available to order today, and in stores this Friday, September 18th, starting at $399, or $499 with cellular (LTE).