Apple Watch is a line of smartwatches designed & developed by Apple, and was first released in 2015, the watch quickly became the best-selling wearable device during that period. Apple Watch runs watchOS, whose interface is based around a home screen with circular app icons. The OS can be navigated using the touchscreen or the crown on the side of the watch. The device relies on a wireless connection to an iPhone to perform many functions which includes calling, texting, receiving call, sms and other notifications, and it also comes with a lot of apps which are designed to interact with their iOS counterparts, such as Mail, Phone, Calendar, Messages, Maps, Music, Photos, Reminders, Remote (which can control iTunes and Apple TV), Stocks, and Wallet. The Apple Watch is equipped with fitness tracking (that allows users keep track of the data from their physical activities) and health-oriented attributes designed to help users improve their health and wellbeing. The Apple Watch is available in various versions/models, which includes: Apple Watch Apple Watch Series 1 Apple Watch Series 2 Apple Watch Series 3 Apple Watch Series 4 Apple Watch is charged by means of inductive charging, using a cable similar to the MagSafe cable from Apple's MacBook family of laptops. The battery is stated to last for 18 hours of mixed usage in which an alert is sent when the watch's battery depletes to less than 10 percent. There are clams of the Apple watch being waterproof, this however is not true, although they are water resistant, meaning, they can withstand splashes of water (such as rain and hand washing) but should not be submerged in water as they can begin to display erratic behavior.