key fob

noun3

1. •
   An item carried on a key ring either as decoration or for security.
2. •
   A passive wireless electronic device that usually uses RFID technology to control access to buildings, containers, computers, etc. by being placed near a detector.
3. •
   An active wireless electronic device that controls access to buildings or vehicles, such as a remote control for a car door lock.

   • She finds her key fob and unlocks the doors. — 2020