A family of smartwatches from Apple that debuted in April 2015 with more than 40 models from USD $349 to $17,000. Compatible with iPhones starting with the iPhone 5, the screen's Force Touch senses the difference between a tap and a press to enable two modes of touch interaction. Available in two case sizes (38/42mm) and numerous band styles, the watch's Taptic Engine "taps" the wearer on the wrist for notifications.Apple Watch 2 and 3Five months after the unveiling, the Series 2 was introduced, including Hermes-branded models (see below). In 2017, the Series 3 improved performance and added an altimeter and Apple Music streaming. However, the cellular option in the 3 made it a stand-alone cellphone (Series 3 models without cellular are less expensive than their Series 2 counterparts). Approximately eight million 3s were sold in the last quarter of 2017; more than all the watches exported from Switzerland, the world capital of watchmaking.Apple Watch 4In 2018, with new watch styles available, the fourth incarnation of Apple Watch is .07 millimeter thinner but with a 30% larger screen by reducing the bezel and adding two millimeters to the case sizes (40/44 versus 38/42mm). The fourth-generation CPU, twice as fast as the previous combined with watchOS 5 offers a variety of enhancements. The Digital Crown delivers a click-like feel when scrolling. Along with a new heart sensor, the Crown was enhanced to generate an electrocardiogram with the ECG app. See watchOS.Wi-Fi TooIf the watch was previously paired with the iPhone via Bluetooth but goes out of range, it can use the same Wi-Fi network to send iMessages, an animated sketch, taps and heartbeats to other Apple Watch users (see Digital Touch). The device can also run Siri over Wi-Fi.