A beacon is a small device that uses Bluetooth technology to communicate with nearby devices, such as smartphones or tablets. Beacons are often used in location-based marketing and advertising, where they can send push notifications, offers, or other content to users who have the appropriate app installed on their device and are within range of the beacon. For example, a retailer may use beacons in their store to send special offers or promotions to customers who are shopping in the store. Beacons can also be used to track and analyze customer behavior, such as how long they spend in different parts of the store, which can help retailers to optimize their marketing and operations.