Passive RFID tags do not contain batteries, power is supplied by a reader. A coiled antenna within the tag forms a magnetic field which the tag draws power from. Once powered, radio waves are emitted which are then detectable by the reader and information is then fed back to a computer.
RFID HF LF Sticker 3M Adhesive PVC coin tagcontain small microchips with little aerials which can store a small amount of information for transfer to another NFC device.The tag contains electronically stored information which can be read from up to several meters (yards) away. Unlike a bar code, the tag does not need to be within line of sight of the reader and may be embedded in the tracked object.