Apple has unveiled two new versions of its smartwatch at a digital event on 15 September – Apple Watch Series 6, which is the brand's most advanced smartwatch yet, and a cheaper model, Apple Watch SE. Apple also unveiled Apple Fitness+, its new subscription service for virtual fitness classes.

The new Apple Watch Series 6 has a square design and always-on screen, as did its predecessor, however the Series 6 has a 20 per cent faster processor and a screen that’s 2.5 times brighter than the Series 5 when outside and not actively being used.

The Series 6, in addition to an ECG monitor, now features oxygen saturation (SpO2) measurement, which Apple says allows users to better understand their overall fitness and wellness. SpO2 has been a subject of increased interest worldwide since COVID-19, as oxygen saturation is a measure of general respiratory health, and a low reading may signal illness.

The always-on altimeter provides real-time elevation all day by using a new, more power-efficient barometric altimeter, along with GPS and nearby Wi-Fi networks. This feature allows for the detection of small elevation changes above ground level, up and down to the measurement of 1 foot, and can be shown as a new watch face complication or workout metric.

The cheaper Apple Watch SE is billed as "packing the essential features of Apple Watch into a modern design customers love — all at a more affordable price".

It features the largest and most advanced Retina display of all Apple's watches, also featuring the same accelerometer, gyroscope, and always-on altimeter as Apple Watch Series 6.

Both watches can be used with Apple Fitness+, a new virtual workout service from Apple.

Apple said: "Apple Fitness+ intelligently incorporates metrics from Apple Watch for users to visualise right on their iPhone, iPad, or Apple TV, offering a first-of-its-kind personalised workout experience. When a workout is selected and started on any of those devices, the correct workout type will automatically start on Apple Watch. During the session, the metrics from Apple Watch are shown on the screen and come to life for moments of inspiration."

Apple Watch Series 6 (GPS) starts at US$399 and Apple Watch Series 6 (GPS + Cellular) starts at US$499. Apple Watch SE (GPS) starts at US$279 and Apple Watch SE (GPS + Cellular) starts at US$329.