Radio Frequency Identification (RFID) is a type of passive wireless technology that allows items or people to be tracked or matched. It consists of two main parts: tags and readers. The reader emits radio waves and receives signals back from the RFID tag, while the tag uses radio waves to communicate its identity and other information. RFID works through a small electronic device, usually a microchip, that stores information. These devices are usually quite small, sometimes the size of a grain of rice, and can store large amounts of data. Although they do not always emit electricity, some may contain a power source or batteries. The scanners used to read these devices can also provide enough electricity to allow them to read the microchip. The technology has become very widespread in recent years due to its use in the global supply chain and microchipping of pets.