RFID chips are designed to be small and convenient as this article from the Free Press community webpage – Palo Alto – informs us. So convenient in fact that you may not even be aware that RFID is present how you interact with services and products.
“RFID Chips are tiny, nearly microscopic semiconductor chips that emit a radio signal containing digital information when energized by a nearby scanner reader or recorder.
They do no need a battery or internal energy source. They can operate indefinitely, even through animal or human flesh.”
Against RFID in schools 