Apple Watch Series 6 launched today in Cupertino with a blood oxygen sensor and app, new case finishes, and watch OS 7.

The Apple Watch Series 6 has the same design as the Series 5, with an always-on display that is brighter and easier to read, a next-generation always-on altimeter, and a faster S6 System in Package (SiP). There are multiple new premium case finishes such a blue aluminum, product(RED) aluminum, graphite stainless steel, and refined gold steel. Plus the new clasp-less Solo Loop and Braided Solo Loop straps (both pictured top).

The new operating system, watchOS 7, offers Family Setup, sleep tracking, automatic handwashing detection, new workout types, and the ability to curate and share watch faces.

Apple Watch Series 6 greatly expands health functions compared to previous models, most notably the new blood oxygen measuring capabilities.

“To compensate for natural variations in the skin and improve accuracy, the Blood Oxygen sensor employs four clusters of green, red, and infrared LEDs, along with the four photodiodes on the back crystal of Apple Watch, to measure light reflected back from blood. Apple Watch then uses an advanced custom algorithm built into the Blood Oxygen app, which is designed to measure blood oxygen between 70 percent and 100 percent. On-demand measurements can be taken while the user is still, and periodic background measurements occur when they are inactive, including during sleep. All data will be visible in the Health app, and the user will be able to track trends over time to see how their blood oxygen level changes,” according to Apple.

Apple Watch Series 6 (GPS) starts at $399 and Apple Watch Series 6 (GPS + Cellular) starts at $499. Available in the US begins September 18th. There’s also the Apple Watch SE, which uses the chip and design from the Series 5 at a starting price of $279.

Learn more at Apple.