CUPERTINO - Apple launched its next generation smartwatch - the Apple Watch Series 4 - on Wednesday (Sept 12) which features an electrocardiogram (ECG) measuring capability that allows it to take ECG readings any time.

Apple's chief operating officer Jeff Williams, speaking at a special event held at the Steve Jobs Theatre in the tech giant's campus Apple Park, said it is the first ECG product available to consumers over the counter, although this feature will be available only in the United States, and later this year.

While its design might look similar to the previous three generations, the Series 4 is thinner and has a display more than 30 per cent larger than its predecessors.

The Series 4 features a new S4 processor that is said to be two times faster than previous models. In addition, its new accelerometer and gyroscope have twice the dynamic range, with eight times faster sampling and up to 32 g-forces.

The new Series 4 now comes in watch case sizes of 40mm and 44mm, compared to the 38mm and 42mm watch cases of its predecessors. However, watch bands for previous models will still work with Series 4.

Along with the three aluminium finishes anodised in silver, gold and space grey, Apple Watch Series 4 will also come in a gold stainless steel with matching Milanese band, joining the silver and space black stainless steel models.

The Apple Watch Series 4 (GPS) starts from $599 and Apple Watch Series 4 (GPS + Cellular) starts from $749, both featuring the updated design and new health capabilities.

And the Series 4 will be available in Singapore from Sept 21 with the cellular version exclusive with Singtel. Pre-orders for the smartwatch start on Friday Sept 14.