Ever had some weird readings from your Apple Watch, or even wondered if you’re wearing right? Well, don’t worry, AppleInsider found information from Apple on exactly how it wants you to wear the device.

While much of the Apple Watch’s fitness capabilities comes through having internals such as an accelerometer to measure movement or provide fall detection, it also has an array of sensors on the back. If you’ve ever seen someone wearing an Apple Watch too loosely, you’ve seen a bright green light coming from the back. This is the optical heart sensor, which uses photoplethysmography to calculate your heart rate. That back of the Watch, though, must be kept in contact with your skin for that optical and an electrical heart rate sensor to work. The Taptic Engine expects you to be wearing it snugly, and the Wrist Detect feature has to have that skin contact. Apple even provides a diagram recommending the right fit.

Apple’s approach to China has stoked a lot of controversy in recent days. Wired looked at the numbers that may be driving the company’s policy. You may agree with the conclusions. You may disagree. But the article provides some important context to what is going on.

Last week, China temporarily suspended ties with the NBA after Daryl Morey, the general manager of the Houston Rockets, tweeted – and quickly deleted – his support for Hong Kong’s pro-democracy protesters, forcing the NBA to publicly apologise for the move. That same week, Blizzard controversially banned a Hearthstone tournament player after he made a political statement in support of Hong Kong protesters during a post-tournament interview. But more significant are the actions of Apple. The company has removed two apps from its App Store after receiving widespread criticism from Chinese state media. One of these was the app for news website Quartz, which has extensively covered the Hong Kong protests; the other was the HKmap.live app after authorities claimed that protesters were using the app to target and attack the police. These moves by Apple are part of a wider pattern of behaviour by the company to appease China, which has become one of its most important markets. And a closer look at the numbers reveals just how important China has become to the Cupertino-based firm – and how far it’s willing to go to keep the world’s most-populous onside.