A smartwatch (or smart watch) is a computerized wristwatch with functionality that is enhanced beyond timekeeping. While early models can perform basic tasks, such as calculations, translations, and game-playing, modern smartwatches are effectively wearable computers. Many smartwatches run mobile apps, while a smaller number of models run a mobile operating system and function as portable media players, offering playback of FM radio, audio, and video files to the user via a Bluetooth headset. Some smartwatches models, also called watch phones, feature full mobile phone capability, and can make or answer phone calls. Such devices may include features such as a camera, accelerometer, thermometer, altimeter, barometer, compass, chronograph, calculator, cell phone, touch screen, GPS navigation, Map display, graphical display, speaker, scheduler, watch, SDcards that are recognized as a mass storage device by a computer, and rechargeable battery. It may communicate with a wireless headset, heads-up display, insulin pump, microphone, modem, or other devices. Some also have “sport watch” functionality with activity tracker features (also known as “fitness tracker”) as seen in GPS watches made for Training, Diving, and Outdoor sports. Functions may include training programs (such as intervals), Lap times, speed display, GPS tracking unit, Route tracking, dive computer, heart rate monitor compatibility, Cadence sensor compatibility, and compatibility with sport transitions (as in triathlons). Like other computers, a smartwatch may collect information from internal or external sensors. It may control, or retrieve data from, other instruments or computers. It may support wireless technologies like Bluetooth, Wi-Fi, and GPS. However, it is possible a “wristwatch computer” may just serve as a front end for a remote system, as in the case of watches utilizing cellular technology or Wi-Fi.