Apple just unveiled its latest high-end smartwatch, which has advanced health-tracking features and comes in 2 new colors

• Apple on Tuesday unveiled its latest high-end smartwatch, the Apple Watch Series 6.
• The new watch has a new health sensor to measures blood oxygen levels and comes in four colors: blue, red, gold, and graphite.
• The Apple Watch Series 6 starts at $399 and goes on sale this Friday.
• Unlike in previous years, Apple is also offering a less expensive watch, the Apple Watch SE, that starts at $279.

Apple has unveiled its latest high-end smartwatch: the Apple Watch Series 6.

The new watch, which Apple showed off at its annual hardware event on Tuesday, marked a departure from Apple's typical lineup. Rather than offering one new watch and discounting older models, Apple debuted two watches: one premium version, the Series 6, and one lower-cost version, the Apple Watch SE.

The higher-end Series 6 has several new features to differentiate it from its predecessor, the Series 5, including a new chip that Apple said would make the watch 20% faster than the previous generation and, most notably, a new health sensor that measures blood oxygen levels.

The sensor works by shining infrared light onto the user's wrist and measuring how much light is reflected back. It takes about 15 seconds to measure blood oxygen levels, and measurements can be recorded while the wearer sleeps, Apple said.

The Series 6 will also be able to track elevation changes in real time, have an always-on display that's easy to see on sunny days, and come with multiple new watch faces, Apple said.

The new watch will come in four colors — blue, red, gold, and graphite — and Apple created two types of bands: a Solo Loop that's one continuous piece of stretchable material, and a braided Solo Loop that's made from recycled yarn.

To make the watch more accessible to families, Apple is offering a new feature called family setup that allows users to pair multiple watches with one iPhone but creates an account for each user. The feature is available for cellular models of the Apple Watch Series 4 or newer.

The Apple Watch Series 6 starts at $399 and goes on sale Friday. Unlike with past models, Apple will not include a power adapter in the box to cut down on waste.