The 10th version of the Apple Watch was announced at Apple’s event on Monday and features a 40 percent brighter wide-angle OLED screen that is larger than the display on the Apple Watch Ultra.

The new Apple Watch Series 10 is just 9.7 millimeters thick, making it 10 percent thinner than the Apple Watch Series 9. Apple says the larger OLED screen, the largest ever used in an Apple Watch, allows the wearable to display an additional line of text on the screen, making it easier for users to check emails and messages at a glance.

The Series 10 is powered by Apple’s new S10 chip with quad-core Neural Engine, it has a polished aluminum finish and a new metal back that integrates the smartwatch’s various antennas. It is still waterproof to a depth of 50 meters and has a larger charging coil that allows for faster charging. The Series 10’s battery can be charged to 80 percent of its capacity in just 30 minutes.

The Series 10 will be the first Apple Watch to feature sleep apnea detection (pending FDA approval), which uses the smartwatch’s accelerometer to monitor the user’s breathing overnight. It’s a condition where people suddenly stop breathing while they sleep. It’s usually detected using devices that monitor the patient’s heart, breathing patterns, brain activity, and even limb movements. If the Series 10 detects signs of sleep apnea, it will alert the user and generate a detailed report that can be sent to a doctor.

The Apple Watch Series 10 will be available in three finishes: natural, gold and dark slate gray, as well as a titanium version. It will be available on September 20 and will start at $399.

The 10th Apple Watch arrives after nearly a decade of iterative updates to the company’s smartwatch. Apple initially focused on marketing it as a fashion accessory and iPhone companion, but through hardware upgrades and new features in watchOS, the Apple Watch has since become a major health and fitness tool.

The Series 10 is the successor to last year’s Apple Watch Series 9, which introduced features such as a “double-tap” gesture for answering calls with one hand, a brighter screen, and a new S9 SiP (System in Package) that allows for faster processing of Siri requests on the device.

Previously, the Apple Watch Series 8 featured additional temperature sensors for improved health monitoring as well as fall detection. It was also launched at the same time as the Apple Watch Ultra, which featured a larger screen, additional buttons and a more robust and durable design to compete with products from companies like Garmin and Suunto focused on outdoor activities.

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