Senior citizens aren’t usually the first people lining up to buy the latest high-tech gadget, but Apple’s new Series 4 watch could provide a potentially life-saving service to the elderly—and others. As The Telegraph reports, the watch is equipped with technology capable of detecting when someone has fallen.

If a hard fall occurs, a message on the dial prompts the wearer to select “emergency SOS” or “I fell, but I’m OK.” If the user is motionless for 60 seconds afterward, the watch automatically places a call to emergency responders, and sends a message to emergency contacts with location information.

Apple

The watch, whose features were highlighted at the annual Apple product launch in Silicon Valley on Wednesday, could prove a serious competitor to Life Alert, a popular medical alert system.

An accelerometer and gyroscope inside the watch allow it to analyze the wearer’s “wrist trajectory and impact acceleration,” according to an Apple statement, but determining when someone has fallen isn’t so simple. Apple had to figure out a specific algorithm based on a range of bodily motions.

“Identifying a fall sounds straightforward, but it requires a large amount of data and analysis,” Jeff Williams, Apple’s chief operating officer, said. “With falls, there’s this repeatable motion pattern that happens. When you trip, your arms go forward; but when you slip, your arms go upward.”

This isn’t the only new health feature, either. The new Apple Watch also contains an electrical heart rate sensor, which lets it take an electrocardiogram (ECG or EKG) and monitor for any irregularities. This marks the first time a product containing an EKG is available over-the-counter to consumers, according to The Telegraph.

The GPS version of the Apple Watch Series 4 is priced at $399, and the GPS and cellular model costs $499. Orders can be placed beginning September 14, and watches will be available in stores on September 21.

[h/t The Telegraph]