The Apple Watch (marketed stylized as ) is a smartwatch developed by Apple Inc. It incorporates fitness tracking and health-oriented capabilities as well as integration with iOS and other Apple products and services. The device is available in four variants: Apple Watch Sport, Apple Watch, Apple Watch Hermès, and Apple Watch Edition. The Watch is distinguished by different combinations of cases and first or third party interchangeable bands. Apple Watch relies on a wirelessly connected iPhone to perform many of its default functions such as calling and texting. It is compatible with the iPhone 5 or later models running iOS 8.2 or later, through the use of Bluetooth or Wi-Fi. Announced by Tim Cook on September 9, 2014, the device was available for pre-order on April 10 and began shipping on April 24, 2015. The Apple Watch quickly became the best-selling wearable device, with the shipment of 4.2 million smartwatches in the second quarter of 2015, according to analyst firm Canalys.