The NFC (near field communication) tag is made up of an antenna and a small passive IC chip usually on a PET substrate with an adhesive backing; no power source required. Tags have a lifespan of 10 plus years.
Tags come in different capacities up to 1000 bytes. The tags are one-time programmable or rewriteable with the ability to lock.
The tag is activated when you hold your smartphone in close proximity – about ¾”.