RFID（adio-frequency identification ）uses electromagnetic fields to automatically identify and track tags attached to objects.
An RFID tag consists of a tiny radio transponder; a radio receiver and transmitter.
Passive tags are powered by energy from the RFID reader's interrogating radio waves.
When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to inventory goods.
RFID tags are used in many industries. For example, automobile, warehouses, animals, logistic, laundry, tools, tires, pallets, IT equipment and so on.