An RFID reader is a device that uses radio waves to communicate with RFID tags. These tags contain small chips that store information, which the reader can access when in range. RFID readers are commonly used in various applications, such as inventory management, access control, and tracking items in supply chains. The reader emits a radio signal that activates the RFID tag, prompting it to send back its stored data. This process allows for quick and efficient scanning of multiple items without needing direct line-of-sight, making it a valuable tool in modern technology and logistics.