HONG KONG — The newly announced Apple Watch Series 6 continues the company's push to position the wearable as a health and wellness device: it can now track blood-oxygen levels by shooting red and infrared light — and the whole process takes 15 seconds.

"You can have [the Watch] monitor your blood-oxygen levels during sleep and when you wake up, the findings will be on your Watch and iPhone app," explains an Apple executive, adding that the company is working with three medical centres in the US to determine medical indicators from the results.

While other wearables such as the Fitbit Versa 2 can already track blood-oxygen levels — otherwise known as SpO2 — the new Watch 6 can do it actively through the day, automatically.

SpO2 readings can be shared with health professionals with a few taps on the iPhone Health app.

The new feature is meant to be as much about detecting potential developing health problems as it is about alerting users of an existing one.

Powering the new sensor is the S6 chip, which is based on the architecture of the A13 Bionic chip used in the iPhone 11 lines. Apple says apps will launch 20 per cent faster on the Apple Watch 6 than the 5, and there will be a new brighter "Always-On" display.

The Apple Watch Series 6, which starts at US$399 (S$543), is a highlight of yesterday's Apple September (online-only) event. The usual star of its show, the iPhone, was absent as its launch has been delayed, likely until October.

The other new Watch, the Watch SE, is a relatively low-cost model. Prices start at US$279, it runs on the S5 chip that's currently used in the Watch 5, and keeps many of the software features of the main Apple Watch line, such as the handwashing reminder, fall detection and heart rate tracking, but lacks the blood-oxygen monitor.

Apple also introduced new iPads. The iPad Air has an aesthetic closer to the iPad Pro line — thin bezels and no circular home button. Inside the tablet is Apple's newest A14 Bionic chip, the world's first 5nm mobile processor with a six-core CPU and 11.8 billion transistors.

Apple's A-series chip usually makes its debut in new iPhones, so it's notable that a mid-tier iPad will beat Apple's flagship product to the market with the chip this year.

The introduction of the US$599 iPad Air with a 10.9-inch screen does make the more expensive 11-inch iPad Pro seem redundant, since they have near identical designs and run the same software. The key differences are that the Air has a traditional 60Hz refresh rate, the Pro runs at 120Hz; and the Air has kept the capacitive fingerprint scanner located on the side of the device instead of Face ID.

For fans of the Apple circular home button, there's also a new basic iPad that keeps the iconic (and old) design.

It's clearly the lowest on the iPad pecking order: prices start at US$329 and it runs on the two-year-old A12 chip. Still, it should be more than enough for students and basic users. SOUTH CHINA MORNING POST