People arriving in Hong Kong must wear tracking bracelets for 2 weeks or face jail time. Here's how they work.

• In Hong Kong, anyone arriving from a foreign country is required to wear a wristband and follow a 14 day quarantine.
• Some of the devices are small wristbands with a QR code, which wearers are supposed to use to check in with an app on their phones.
• Recently, some arrivals have been given larger bracelets capable of tracking their movements.
• Visit Business Insider's homepage for more stories.

Hong Kong has taken a stricter approach to coronavirus quarantines than many countries, using wristbands to enforce a mandatory 14 day quarantine on anyone arriving from another country.

Hong Kong, along with Singapore and Taiwan, initially seemed to have gotten ahead of COVID-19, the coronavirus disease, with few infections. Then, a new wave of coronavirus cases spiked, largely from travelers from abroad. In response, arrivals have been given wearable technology to ensure that they follow the 14 day quarantine orders, or risk six months in jail and a $645 fine, plus possible social media backlash.

Here are what the bracelets are like, and how they work.

Hong Kong Health Secretary Sophia Chan said that mandatory quarantines for visitors will be extended to at least June 7.

Hong Kong quarantine wrist band.      Photo by ISAAC LAWRENCE/AFP via Getty Images/Mary Meisenzahl

Source: Reuters

As of March 20, Hong Kong authorities had only activated a third of bracelets,.

Hong Kong quarantine wrist band.      Photo by ISAAC LAWRENCE/AFP via Getty Images/Mary Meisenzahl

Source: Reuters

The tracking bracelets are larger and more intrusive, bigger than a typical watch.

Hong Kong quarantine wrist band.      Photo by ISAAC LAWRENCE/AFP via Getty Images

Some of the 60,000 bracelets issued by the Department of Health and the Innovation and Technology Bureau are larger than the wristbands, and capable of tracking wearers independently of their phones.

Hong Kong quarantine wrist band.      Photo by ISAAC LAWRENCE/AFP via Getty Images

Source: The New York Times

After two weeks, a text informs wearers that their quarantine period is over, and they can cut off the wristband.

Hong Kong quarantine wrist band.      Photo by ANTHONY WALLACE/AFP via Getty Images

One person told the New York Times that after mapping her apartment, if her phone was in an unregistered space it would start beeping, and could only be stopped by scanning each member of the family's wristband QR code.

Hong Kong airport.      Photo by ANTHONY WALLACE/AFP via Getty Images

Wearers are prompted to walk around the perimeter of their apartment, or wherever they would be spending the quarantine period, to map it out for the app.

Hong Kong quarantine wrist band.      Willie Siau / Echoes Wire/Barcroft Media via Getty Images

The StayHomeSafe app is used to connect to the wrist bands and periodically rescan. If someone tries to break quarantine, it issues a warning.

StayHomeSafe app.      Google Play

Source: QZ

Arrivals received a PIN on their phones, which allowed them to connect the app to the wristband.

Hong Kong quarantine wrist band.      Photo by ANTHONY WALLACE/AFP via Getty Images

Source: The New York Times

Authorities give out wrist bands with a QR code, and instruct wearers to download a corresponding app. They also receive handouts detailing consequences for breaking quarantine orders.

Hong Kong airport.      Photo by ANTHONY WALLACE/AFP via Getty Images

Source: CNBC

Bracelets became mandatory for arrivals in Hong Kong on March 18.

Hong Kong airport.      Photo by ANTHONY WALLACE/AFP via Getty Images