Fitness tracker in the context of "Wearable computer"

Electronic tagging is a form of surveillance that uses an electronic device affixed to a person to monitor their location or physiological state. It is a specific application of asset tracking technology where the "asset" being monitored is a person.

In some jurisdictions, an electronic tag fitted above the ankle is used for individuals as part of their bail or probation conditions. It is also used in healthcare settings and in immigration contexts. Electronic tagging can be used in combination with a GPS tracking unit for wide-area monitoring, but for short-range monitoring of a person, radio frequency technology is often used.

Wearable technology is a category of small electronic and mobile devices with wireless communications capability designed to be worn on the human body and are incorporated into gadgets, accessories, or clothes. Common types of wearable technology include smartwatches, fitness trackers, and smartglasses. Wearable electronic devices are often close to or on the surface of the skin, where they detect, analyze, and transmit information such as vital signs, and/or ambient data and which allow in some cases immediate biofeedback to the wearer. Wearable devices collect vast amounts of data from users making use of different behavioral and physiological sensors, which monitor their health status and activity levels. Wrist-worn devices include smartwatches with a touchscreen display, while wristbands are mainly used for fitness tracking but do not contain a touchscreen display.

Wearable devices such as activity trackers are an example of the Internet of things, since "things" such as electronics, software, sensors, and connectivity are effectors that enable objects to exchange data (including data quality) through the internet with a manufacturer, operator, and/or other connected devices, without requiring human intervention. Wearable technology offers a wide range of possible uses, from communication and entertainment to improving health and fitness, however, there are worries about privacy and security because wearable devices have the ability to collect personal data.

The Apple Watch is a smartwatch developed and marketed by Apple. It has fitness tracking, health-oriented capabilities, and wireless telecommunication, and integrates with watchOS and other Apple products and services. The first Apple Watch was released in April 2015, and quickly became the world's best-selling wearable device: 4.2 million were sold in the second quarter of fiscal 2015, and more than 115 million people were estimated to use an Apple Watch as of December 2022. Apple has introduced a new generation of the Apple Watch with improved internal components each September – each labeled by Apple as a 'Series', with certain exceptions.

Each Series has been initially sold in multiple variants defined by the watch casing's material, colour, and size (except for the budget watches Series 1 and SE, available only in aluminium, and the Ultra, available only in 49 mm titanium), and beginning with the Series 3, by the option in the aluminium variants for LTE cellular connectivity, which comes standard with the other materials. The band included with the watch can be selected from multiple options from Apple, and watch variants in aluminium co-branded with Nike and in stainless steel co-branded with Hermès are also offered, which include exclusive bands and colours. Any user may use digital watch faces carrying those companies' branding.